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<?xml version="1.0" encoding="utf-8"?>
<search>
<entry>
<title>卷积、池化计算</title>
<link href="/2024/08/31/juan-ji-chi-hua-ji-suan/"/>
<url>/2024/08/31/juan-ji-chi-hua-ji-suan/</url>
<content type="html"><![CDATA[<p>要设计卷积神经网络的结构，必须<strong>匹配层与层之间的输入与输出的尺寸</strong>，这就需要较好的计算输出尺寸</p><h2 id="1-卷积"><a href="#1-卷积" class="headerlink" title="1. 卷积"></a>1. 卷积</h2><p>卷积层的作用是<strong>提取输入图片中的信息，这些信息被称为图像特征</strong>，这些特征是由图像中的每个像素通过组合或者独立的方式所体现，比如图片的纹理特征，颜色特征。</p><p>卷积层有很多卷积核，通过做越来越多的卷积，提取到的图像特征会越来越抽象。</p><p>卷积后，图像尺寸计算公式为：**(图像大小 - 卷积核大小 + 2<em>填充值) / 步长 + 1</em>*</p><p>即：</p><p><img src="/2024/08/31/juan-ji-chi-hua-ji-suan/%E5%8D%B7%E7%A7%AF%E5%85%AC%E5%BC%8F.png"></p><pre class="line-numbers language-txt" data-language="txt"><code class="language-txt">其中：N：输出矩阵的大小，N x NW：输入图片的大小，W x WK：卷积核kernel_size大小，K x KP：填充值padding大小S：步长stride大小<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>以resnet50为例，输入为[1, 3, 224, 224]，其中1为 batchsize，3为通道数，224为height和width。</p><p>经过第一层卷积后，其大小为[1,64,112,112]</p><pre class="line-numbers language-python" data-language="python"><code class="language-python">in_channels<span class="token operator">=</span> <span class="token number">3</span> <span class="token operator">//</span>输入通道，RGB图像作为输入时channels为<span class="token number">3</span>out_channels<span class="token operator">=</span> <span class="token number">64</span> <span class="token operator">//</span>输出通道nn<span class="token punctuation">.</span>Conv2d<span class="token punctuation">(</span>in_channels<span class="token punctuation">,</span> out_channels<span class="token punctuation">,</span> kernel_size<span class="token operator">=</span><span class="token number">7</span><span class="token punctuation">,</span> stride<span class="token operator">=</span><span class="token number">2</span><span class="token punctuation">,</span> padding<span class="token operator">=</span><span class="token number">3</span><span class="token punctuation">,</span> bias<span class="token operator">=</span><span class="token boolean">False</span><span class="token punctuation">)</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span></span></code></pre><p>N = (W − K + 2P ) / S + 1 = (224 - 7 + 2 x 3) / 2 + 1 = 112</p><p><strong>对矩阵和公式的理解：</strong></p><p>1为batchsize，不改变。<br>对于通道数，会生成与设定的输出通道个数相同个数的卷积核，对图片进行卷积，即<strong>卷积核的个数等于输出特征图的通道数</strong>。<br>得到最终输出大小为[1,64,112,112]<br>(W − K + 2P )相当于计算除了第一次卷积后剩下的可用来卷积的大小<br>(W − K + 2P ) / S为按照S大小的步长在刚刚得到的大小上可以向后移动多少次，即：还可以做几次卷积<br>因为不包括第一次卷积，所以再加上一个1，<br>即N = (W − K + 2P )/S+1<br>输出大小 = （图片宽或高 - 卷积核大小 + padding大小）/ 步长 + 1<br>对于宽和高不同的图片可分别用上述公式计算，得到最终的输出大小</p><p>卷积动态图解参考：<br><a href="https://cs231n.github.io/assets/conv-demo/index.html">https://cs231n.github.io/assets/conv-demo/index.html</a></p><h2 id="2-池化"><a href="#2-池化" class="headerlink" title="2. 池化"></a>2. 池化</h2><p>池化层的作用是对卷积层中提取的特征进行挑选，分为<strong>最大池化</strong>和<strong>平均池化</strong>，就是对所有相应位置的数求<strong>最大</strong>或<strong>平均值</strong>，一般用来将高和宽降维。而1*1卷积中的降维降的是通道数的维度。</p><p>最大池化：Max Pooling，取窗口内的最大值作为输出</p><p><img src="/2024/08/31/juan-ji-chi-hua-ji-suan/%E6%9C%80%E5%A4%A7%E6%B1%A0%E5%8C%96.png"></p><p>平均池化：Avg Pooling，去窗口内所有值的平均值作为输出</p><p><img src="/2024/08/31/juan-ji-chi-hua-ji-suan/%E5%B9%B3%E5%9D%87%E6%B1%A0%E5%8C%96.png"></p><p>池化后，图像尺寸的计算公式为：**(图像大小 - 池化核大小 + 2<em>填充值) / 步长 + 1</em>*</p><p>即：</p><p><img src="/2024/08/31/juan-ji-chi-hua-ji-suan/%E6%B1%A0%E5%8C%96%E5%85%AC%E5%BC%8F.png"></p><pre class="line-numbers language-none"><code class="language-none">其中：N：输出矩阵的大小，N x NW：输入图片的大小，W x WK：池化核kernel_size大小，K x KP：填充值padding大小。池化一般不使用填充padding。S：步长stride大小<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>池化会对特征进行降维，但是<strong>不会改变通道数</strong></p><p>示例：</p><pre class="line-numbers language-python" data-language="python"><code class="language-python"><span class="token keyword">import</span> torch<span class="token keyword">import</span> torch<span class="token punctuation">.</span>nn <span class="token keyword">as</span> nn<span class="token comment"># 四维分别对应：(batch_size,channel,H,W)</span>im <span class="token operator">=</span> torch<span class="token punctuation">.</span>randn<span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">64</span><span class="token punctuation">,</span> <span class="token number">112</span><span class="token punctuation">,</span> <span class="token number">112</span><span class="token punctuation">)</span><span class="token comment"># 卷积核为3*3，步长为2，上下左右各填充1行</span>c <span class="token operator">=</span> nn<span class="token punctuation">.</span>MaxPool2d<span class="token punctuation">(</span>kernel_size<span class="token operator">=</span><span class="token number">3</span><span class="token punctuation">,</span> stride<span class="token operator">=</span><span class="token number">2</span><span class="token punctuation">,</span> padding<span class="token operator">=</span><span class="token number">1</span><span class="token punctuation">)</span>output <span class="token operator">=</span> c<span class="token punctuation">(</span>im<span class="token punctuation">)</span><span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">"原张量尺寸："</span><span class="token punctuation">)</span><span class="token keyword">print</span><span class="token punctuation">(</span>im<span class="token punctuation">.</span>shape<span class="token punctuation">)</span><span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">"经最大池化处理后的张量尺寸："</span><span class="token punctuation">)</span><span class="token keyword">print</span><span class="token punctuation">(</span>output<span class="token punctuation">.</span>shape<span class="token punctuation">)</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>原张量尺寸为：[1, 64, 112, 112]</p><p>池化后张量尺寸为：[1, 64, 56, 56]</p>]]></content>
<categories>
<category> 深度学习 </category>
</categories>
<tags>
<tag> 深度学习基础 </tag>
<tag> 卷积 </tag>
<tag> 池化 </tag>
</tags>
</entry>
<entry>
<title>深度学习模型训练全过程</title>
<link href="/2024/08/29/shen-du-xue-xi-mo-xing-xun-lian-quan-guo-cheng/"/>
<url>/2024/08/29/shen-du-xue-xi-mo-xing-xun-lian-quan-guo-cheng/</url>
<content type="html"><![CDATA[<p>本文记录学习深度学习模型训练的流程，包括：数据准备、定义并调用模型、训练模型、评估模型、保存模型、测试模型等</p><h2 id="1-环境准备"><a href="#1-环境准备" class="headerlink" title="1. 环境准备"></a>1. 环境准备</h2><p>首先引入一些深度学习模型所需要的库和包</p><pre class="line-numbers language-python" data-language="python"><code class="language-python"><span class="token keyword">import</span> numpy <span class="token keyword">as</span> np<span class="token keyword">import</span> torch<span class="token keyword">import</span> torch<span class="token punctuation">.</span>nn <span class="token keyword">as</span> nn<span class="token keyword">import</span> torch<span class="token punctuation">.</span>optim <span class="token keyword">as</span> optim<span class="token keyword">import</span> torchvision<span class="token keyword">import</span> torchvision<span class="token punctuation">.</span>transforms <span class="token keyword">as</span> transforms<span class="token keyword">from</span> torch<span class="token punctuation">.</span>utils<span class="token punctuation">.</span>data <span class="token keyword">import</span> DataLoader<span class="token keyword">from</span> torch<span class="token punctuation">.</span>utils<span class="token punctuation">.</span>tensorboard <span class="token keyword">import</span> SummaryWriter<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="2-数据准备"><a href="#2-数据准备" class="headerlink" title="2. 数据准备"></a>2. 数据准备</h2><p>定义数据变换；</p><p>下载并加载训练集和测试集；</p><p>创建数据加载器</p><pre class="line-numbers language-python" data-language="python"><code class="language-python"><span class="token keyword">def</span> <span class="token function">get_training_dataloader</span><span class="token punctuation">(</span>mean<span class="token punctuation">,</span> std<span class="token punctuation">,</span> batch_size<span class="token operator">=</span><span class="token number">16</span><span class="token punctuation">,</span> num_workers<span class="token operator">=</span><span class="token number">2</span><span class="token punctuation">,</span> shuffle<span class="token operator">=</span><span class="token boolean">True</span><span class="token punctuation">)</span><span class="token punctuation">:</span> <span class="token triple-quoted-string string">""" return training dataloader Args: mean: mean of cifar100 training dataset std: std of cifar100 training dataset path: path to cifar100 training python dataset batch_size: dataloader batchsize num_workers: dataloader num_works shuffle: whether to shuffle Returns: train_data_loader:torch dataloader object """</span><span class="token comment">#对数据进行随机变换生成新的训练样本，提高泛化能力，减少过拟合；将不同格式的数据转换为模型可以处理的统一格式；归一化</span> transform_train <span class="token operator">=</span> transforms<span class="token punctuation">.</span>Compose<span class="token punctuation">(</span><span class="token punctuation">[</span> <span class="token comment">#定义数据变换，一个数据预处理流水线</span> <span class="token comment">#transforms.ToPILImage(),</span> transforms<span class="token punctuation">.</span>RandomCrop<span class="token punctuation">(</span><span class="token number">32</span><span class="token punctuation">,</span> padding<span class="token operator">=</span><span class="token number">4</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token comment">#随机裁剪图像到 32x32 大小，裁剪前在图像周围填充 4 个像素</span> transforms<span class="token punctuation">.</span>RandomHorizontalFlip<span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token comment">#以一定的概率随机水平翻转图像</span> transforms<span class="token punctuation">.</span>RandomRotation<span class="token punctuation">(</span><span class="token number">15</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token comment">#随机旋转图像，旋转角度在 -15 度到 15 度之间</span> transforms<span class="token punctuation">.</span>ToTensor<span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token comment">#将图像从 PIL 图像或 numpy 数组转换为 PyTorch 张量</span> transforms<span class="token punctuation">.</span>Normalize<span class="token punctuation">(</span>mean<span class="token punctuation">,</span> std<span class="token punctuation">)</span> <span class="token comment">#使用给定的均值和标准差对图像进行归一化处理</span> <span class="token punctuation">]</span><span class="token punctuation">)</span> <span class="token comment">#cifar100_training = CIFAR100Train(path, transform=transform_train)</span> cifar100_training <span class="token operator">=</span> torchvision<span class="token punctuation">.</span>datasets<span class="token punctuation">.</span>CIFAR100<span class="token punctuation">(</span>root<span class="token operator">=</span><span class="token string">'./data'</span><span class="token punctuation">,</span> train<span class="token operator">=</span><span class="token boolean">True</span><span class="token punctuation">,</span> download<span class="token operator">=</span><span class="token boolean">True</span><span class="token punctuation">,</span> transform<span class="token operator">=</span>transform_train<span class="token punctuation">)</span> cifar100_training_loader <span class="token operator">=</span> DataLoader<span class="token punctuation">(</span> cifar100_training<span class="token punctuation">,</span> shuffle<span class="token operator">=</span>shuffle<span class="token punctuation">,</span> num_workers<span class="token operator">=</span>num_workers<span class="token punctuation">,</span> batch_size<span class="token operator">=</span>batch_size<span class="token punctuation">)</span> <span class="token keyword">return</span> cifar100_training_loader<span class="token keyword">def</span> <span class="token function">get_test_dataloader</span><span class="token punctuation">(</span>mean<span class="token punctuation">,</span> std<span class="token punctuation">,</span> batch_size<span class="token operator">=</span><span class="token number">16</span><span class="token punctuation">,</span> num_workers<span class="token operator">=</span><span class="token number">2</span><span class="token punctuation">,</span> shuffle<span class="token operator">=</span><span class="token boolean">True</span><span class="token punctuation">)</span><span class="token punctuation">:</span> <span class="token triple-quoted-string string">""" return training dataloader Args: mean: mean of cifar100 test dataset std: std of cifar100 test dataset path: path to cifar100 test python dataset batch_size: dataloader batchsize num_workers: dataloader num_works shuffle: whether to shuffle Returns: cifar100_test_loader:torch dataloader object """</span> transform_test <span class="token operator">=</span> transforms<span class="token punctuation">.</span>Compose<span class="token punctuation">(</span><span class="token punctuation">[</span> <span class="token comment">#定义数据变换</span> transforms<span class="token punctuation">.</span>ToTensor<span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> transforms<span class="token punctuation">.</span>Normalize<span class="token punctuation">(</span>mean<span class="token punctuation">,</span> std<span class="token punctuation">)</span> <span class="token punctuation">]</span><span class="token punctuation">)</span> <span class="token comment">#cifar100_test = CIFAR100Test(path, transform=transform_test)</span> cifar100_test <span class="token operator">=</span> torchvision<span class="token punctuation">.</span>datasets<span class="token punctuation">.</span>CIFAR100<span class="token punctuation">(</span>root<span class="token operator">=</span><span class="token string">'./data'</span><span class="token punctuation">,</span> train<span class="token operator">=</span><span class="token boolean">False</span><span class="token punctuation">,</span> download<span class="token operator">=</span><span class="token boolean">True</span><span class="token punctuation">,</span> transform<span class="token operator">=</span>transform_test<span class="token punctuation">)</span> cifar100_test_loader <span class="token operator">=</span> DataLoader<span class="token punctuation">(</span> cifar100_test<span class="token punctuation">,</span> shuffle<span class="token operator">=</span>shuffle<span class="token punctuation">,</span> num_workers<span class="token operator">=</span>num_workers<span class="token punctuation">,</span> batch_size<span class="token operator">=</span>batch_size<span class="token punctuation">)</span> <span class="token keyword">return</span> cifar100_test_loader<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="3-模型定义-x2F-调用模型"><a href="#3-模型定义-x2F-调用模型" class="headerlink" title="3. 模型定义/调用模型"></a>3. 模型定义/调用模型</h2><p>自定义一个模型或调用一个模型；</p><p>使用之前需要先实例化模型（以vgg为例）</p><pre class="line-numbers language-python" data-language="python"><code class="language-python"><span class="token comment"># 定义一个模型</span><span class="token keyword">class</span> <span class="token class-name">VGG</span><span class="token punctuation">(</span>nn<span class="token punctuation">.</span>Module<span class="token punctuation">)</span><span class="token punctuation">:</span> <span class="token keyword">def</span> <span class="token function">__init__</span><span class="token punctuation">(</span>self<span class="token punctuation">,</span> features<span class="token punctuation">,</span> num_class<span class="token operator">=</span><span class="token number">100</span><span class="token punctuation">)</span><span class="token punctuation">:</span> <span class="token builtin">super</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span>__init__<span class="token punctuation">(</span><span class="token punctuation">)</span> self<span class="token punctuation">.</span>features <span class="token operator">=</span> features self<span class="token punctuation">.</span>classifier <span class="token operator">=</span> nn<span class="token punctuation">.</span>Sequential<span class="token punctuation">(</span> nn<span class="token punctuation">.</span>Linear<span class="token punctuation">(</span><span class="token number">512</span><span class="token punctuation">,</span> <span class="token number">4096</span><span class="token punctuation">)</span><span class="token punctuation">,</span> nn<span class="token punctuation">.</span>ReLU<span class="token punctuation">(</span>inplace<span class="token operator">=</span><span class="token boolean">True</span><span class="token punctuation">)</span><span class="token punctuation">,</span> nn<span class="token punctuation">.</span>Dropout<span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> nn<span class="token punctuation">.</span>Linear<span class="token punctuation">(</span><span class="token number">4096</span><span class="token punctuation">,</span> <span class="token number">4096</span><span class="token punctuation">)</span><span class="token punctuation">,</span> nn<span class="token punctuation">.</span>ReLU<span class="token punctuation">(</span>inplace<span class="token operator">=</span><span class="token boolean">True</span><span class="token punctuation">)</span><span class="token punctuation">,</span> nn<span class="token punctuation">.</span>Dropout<span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> nn<span class="token punctuation">.</span>Linear<span class="token punctuation">(</span><span class="token number">4096</span><span class="token punctuation">,</span> num_class<span class="token punctuation">)</span> <span class="token punctuation">)</span> <span class="token keyword">def</span> <span class="token function">forward</span><span class="token punctuation">(</span>self<span class="token punctuation">,</span> x<span class="token punctuation">)</span><span class="token punctuation">:</span> output <span class="token operator">=</span> self<span class="token punctuation">.</span>features<span class="token punctuation">(</span>x<span class="token punctuation">)</span> output <span class="token operator">=</span> output<span class="token punctuation">.</span>view<span class="token punctuation">(</span>output<span class="token punctuation">.</span>size<span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span><span class="token punctuation">,</span> <span class="token operator">-</span><span class="token number">1</span><span class="token punctuation">)</span> output <span class="token operator">=</span> self<span class="token punctuation">.</span>classifier<span class="token punctuation">(</span>output<span class="token punctuation">)</span> <span class="token keyword">return</span> output<span class="token keyword">def</span> <span class="token function">make_layers</span><span class="token punctuation">(</span>cfg<span class="token punctuation">,</span> batch_norm<span class="token operator">=</span><span class="token boolean">False</span><span class="token punctuation">)</span><span class="token punctuation">:</span> layers <span class="token operator">=</span> <span class="token punctuation">[</span><span class="token punctuation">]</span> input_channel <span class="token operator">=</span> <span class="token number">3</span> <span class="token keyword">for</span> l <span class="token keyword">in</span> cfg<span class="token punctuation">:</span> <span class="token keyword">if</span> l <span class="token operator">==</span> <span class="token string">'M'</span><span class="token punctuation">:</span> layers <span class="token operator">+=</span> <span class="token punctuation">[</span>nn<span class="token punctuation">.</span>MaxPool2d<span class="token punctuation">(</span>kernel_size<span class="token operator">=</span><span class="token number">2</span><span class="token punctuation">,</span> stride<span class="token operator">=</span><span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">]</span> <span class="token keyword">continue</span> layers <span class="token operator">+=</span> <span class="token punctuation">[</span>nn<span class="token punctuation">.</span>Conv2d<span class="token punctuation">(</span>input_channel<span class="token punctuation">,</span> l<span class="token punctuation">,</span> kernel_size<span class="token operator">=</span><span class="token number">3</span><span class="token punctuation">,</span> padding<span class="token operator">=</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">]</span> <span class="token keyword">if</span> batch_norm<span class="token punctuation">:</span> layers <span class="token operator">+=</span> <span class="token punctuation">[</span>nn<span class="token punctuation">.</span>BatchNorm2d<span class="token punctuation">(</span>l<span class="token punctuation">)</span><span class="token punctuation">]</span> layers <span class="token operator">+=</span> <span class="token punctuation">[</span>nn<span class="token punctuation">.</span>ReLU<span class="token punctuation">(</span>inplace<span class="token operator">=</span><span class="token boolean">True</span><span class="token punctuation">)</span><span class="token punctuation">]</span> input_channel <span class="token operator">=</span> l <span class="token keyword">return</span> nn<span class="token punctuation">.</span>Sequential<span class="token punctuation">(</span><span class="token operator">*</span>layers<span class="token punctuation">)</span><span class="token keyword">def</span> <span class="token function">vgg11_bn</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">:</span> <span class="token keyword">return</span> VGG<span class="token punctuation">(</span>make_layers<span class="token punctuation">(</span>cfg<span class="token punctuation">[</span><span class="token string">'A'</span><span class="token punctuation">]</span><span class="token punctuation">,</span> batch_norm<span class="token operator">=</span><span class="token boolean">True</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><pre class="line-numbers language-python" data-language="python"><code class="language-python"><span class="token comment"># 调用模型并实例化</span><span class="token keyword">from</span> models<span class="token punctuation">.</span>vgg <span class="token keyword">import</span> vgg11_bnnet <span class="token operator">=</span> vgg11<span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token comment"># 实例化模型</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span></span></code></pre><h2 id="4-定义损失函数和优化器"><a href="#4-定义损失函数和优化器" class="headerlink" title="4. 定义损失函数和优化器"></a>4. 定义损失函数和优化器</h2><p>需要定义一个<strong>损失函数</strong>来衡量模型的预测和真实值之间的差异，同时还需要一个<strong>优化器</strong>来更新模型的参数</p><pre class="line-numbers language-python" data-language="python"><code class="language-python">loss_function <span class="token operator">=</span> nn<span class="token punctuation">.</span>CrossEntropyLoss<span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token comment">#交叉熵损失函数。衡量模型预测与真实值之间的差异</span>optimizer <span class="token operator">=</span> optim<span class="token punctuation">.</span>Adam<span class="token punctuation">(</span>net<span class="token punctuation">.</span>parameters<span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> lr<span class="token operator">=</span><span class="token number">0.001</span><span class="token punctuation">)</span> <span class="token comment">#使用自适应矩估计（Adam）优化器</span><span class="token comment"># 或</span>optimizer <span class="token operator">=</span> optim<span class="token punctuation">.</span>SGD<span class="token punctuation">(</span>net<span class="token punctuation">.</span>parameters<span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> lr<span class="token operator">=</span>args<span class="token punctuation">.</span>lr<span class="token punctuation">,</span> momentum<span class="token operator">=</span><span class="token number">0.9</span><span class="token punctuation">,</span> weight_decay<span class="token operator">=</span><span class="token number">5e-4</span><span class="token punctuation">)</span> <span class="token comment">#使用随机梯度下降（SGD）优化器</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span></span></code></pre><p><strong>优化器优劣比较：</strong></p><p><strong>SGD（随机梯度下降）</strong><br><strong>基本思想：</strong> SGD在每一步更新中仅使用一个（或一小批）样本来计算梯度，而不是使用整个数据集。这种方法可以显著减少计算量，使得训练大规模数据集变得可行。<br><strong>学习率：</strong> SGD通常需要手动调整学习率，并且可能会使用如学习率衰减这样的技巧来帮助模型收敛。学习率的选择对SGD的性能影响很大。<br><strong>收敛速度：</strong> SGD的收敛速度通常比较慢，尤其是在接近最小值的平坦区域。<br><strong>泛化能力：</strong> 研究表明，由于SGD的噪声更大，它可能有助于模型找到泛化性能更好的解。</p><p><strong>优点：</strong>对于大数据集，可以更快地进行优化；可以有效地跳出局部最优解。</p><p><strong>缺点：</strong>1. 更新方向不稳定，可能导致优化过程震荡；2. 可能需要较长时间才能收敛；3. 对所有的参数使用相同的学习率。这可能导致优化过程在某些方向上过快，而在其他方向上过慢。</p><p><strong>Momentum（动量优化）</strong></p><p>动量优化在SGD的基础上引入了动量项，使得优化过程可以积累之前的梯度，从而更快地收敛</p><p><strong>优点：</strong>可以加速SGD在相关方向的收敛速度，抑制震荡。</p><p><strong>缺点：</strong>1. 需要人工设置动量参数；2. 可能会导致优化过程在某些方向上过快，从而跳过最优解。</p><p><strong>Adam（自适应矩估计）</strong><br><strong>基本思想：</strong> Adam是一种自适应学习率的优化算法，它结合了动量（Momentum）和RMSprop的优点。Adam会为不同的参数计算不同的自适应学习率。<br><strong>学习率：</strong> Adam自动调整学习率，通常不需要像SGD那样手动微调学习率，这使得Adam在很多情况下都能较快地收敛。<br><strong>收敛速度：</strong> 由于自适应学习率的特性，Adam在初期训练阶段通常比SGD收敛得更快。<br><strong>泛化能力：</strong> 尽管Adam在许多任务中都显示出了较快的收敛速度，但一些研究表明，对于某些问题，Adam可能导致过拟合，泛化能力不如SGD。<br><strong>优点：</strong>既可以加速优化，又可以自动调整学习率，对于深度学习模型的优化效果较好。</p><p><strong>缺点：</strong>1. 需要人工设置初始学习率和两个衰减系数；2. Adam优化器的收敛性并不是单调的，这可能会导致在训练过程中出现波动，从而影响模型的性能和稳定性；3. Adam优化器在训练初期阶段对梯度的估计存在偏差，但通过偏差纠正可以降低其影响，然而这种偏差纠正可能会带来额外的计算负担。</p><h2 id="5-模型训练"><a href="#5-模型训练" class="headerlink" title="5. 模型训练"></a>5. 模型训练</h2><p>模型训练包括：前向传播、计算损失、反向传播、参数更新。</p><pre class="line-numbers language-python" data-language="python"><code class="language-python">net<span class="token punctuation">.</span>train<span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token comment">#设置神经网络为训练模式</span><span class="token keyword">for</span> batch_index<span class="token punctuation">,</span> <span class="token punctuation">(</span>images<span class="token punctuation">,</span> labels<span class="token punctuation">)</span> <span class="token keyword">in</span> <span class="token builtin">enumerate</span><span class="token punctuation">(</span>cifar100_training_loader<span class="token punctuation">)</span><span class="token punctuation">:</span> <span class="token comment">#遍历训练数据加载器</span> optimizer<span class="token punctuation">.</span>zero_grad<span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token comment">#将优化器中所有参数的梯度清零，以便进行新一轮的梯度计算</span> outputs <span class="token operator">=</span> net<span class="token punctuation">(</span>images<span class="token punctuation">)</span> <span class="token comment">#将输入图像传递给神经网络进行前向传播</span> loss <span class="token operator">=</span> loss_function<span class="token punctuation">(</span>outputs<span class="token punctuation">,</span> labels<span class="token punctuation">)</span> <span class="token comment">#计算输出和标签之间的损失</span> loss<span class="token punctuation">.</span>backward<span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token comment">#进行反向传播，计算损失对网络参数的梯度</span> optimizer<span class="token punctuation">.</span>step<span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token comment">#根据计算的梯度更新网络参数</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="6-模型评估"><a href="#6-模型评估" class="headerlink" title="6. 模型评估"></a>6. 模型评估</h2><p>在测试集上评估模型的性能，看它在未见过的数据集上的性能表现如何</p><pre class="line-numbers language-python" data-language="python"><code class="language-python">net<span class="token punctuation">.</span><span class="token builtin">eval</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token comment">#将神经网络设置为评估模式，禁用 dropout 和 batch normalization 等训练相关的操作</span>test_loss <span class="token operator">=</span> <span class="token number">0.0</span> <span class="token comment"># cost function error</span>correct <span class="token operator">=</span> <span class="token number">0.0</span><span class="token keyword">for</span> <span class="token punctuation">(</span>images<span class="token punctuation">,</span> labels<span class="token punctuation">)</span> <span class="token keyword">in</span> cifar100_test_loader<span class="token punctuation">:</span> <span class="token keyword">if</span> args<span class="token punctuation">.</span>gpu<span class="token punctuation">:</span> images <span class="token operator">=</span> images<span class="token punctuation">.</span>cuda<span class="token punctuation">(</span><span class="token punctuation">)</span> labels <span class="token operator">=</span> labels<span class="token punctuation">.</span>cuda<span class="token punctuation">(</span><span class="token punctuation">)</span> outputs <span class="token operator">=</span> net<span class="token punctuation">(</span>images<span class="token punctuation">)</span> loss <span class="token operator">=</span> loss_function<span class="token punctuation">(</span>outputs<span class="token punctuation">,</span> labels<span class="token punctuation">)</span> test_loss <span class="token operator">+=</span> loss<span class="token punctuation">.</span>item<span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token comment">#累加损失值</span> _<span class="token punctuation">,</span> preds <span class="token operator">=</span> outputs<span class="token punctuation">.</span><span class="token builtin">max</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span> <span class="token comment">#获取输出中每行最大值的索引，即预测的类别</span> correct <span class="token operator">+=</span> preds<span class="token punctuation">.</span>eq<span class="token punctuation">(</span>labels<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token builtin">sum</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token comment">#将预测正确的样本数累加</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="7-保存模型"><a href="#7-保存模型" class="headerlink" title="7. 保存模型"></a>7. 保存模型</h2><p>将训练好的模型保存下来，方便后续使用或部署</p><pre class="line-numbers language-python" data-language="python"><code class="language-python"><span class="token comment">#start to save best performance model after learning rate decay to 0.01</span><span class="token keyword">if</span> epoch <span class="token operator">></span> settings<span class="token punctuation">.</span>MILESTONES<span class="token punctuation">[</span><span class="token number">1</span><span class="token punctuation">]</span> <span class="token keyword">and</span> best_acc <span class="token operator"><</span> acc<span class="token punctuation">:</span> weights_path <span class="token operator">=</span> checkpoint_path<span class="token punctuation">.</span><span class="token builtin">format</span><span class="token punctuation">(</span>net<span class="token operator">=</span>args<span class="token punctuation">.</span>net<span class="token punctuation">,</span> epoch<span class="token operator">=</span>epoch<span class="token punctuation">,</span> <span class="token builtin">type</span><span class="token operator">=</span><span class="token string">'best'</span><span class="token punctuation">)</span> <span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">'saving weights file to {}'</span><span class="token punctuation">.</span><span class="token builtin">format</span><span class="token punctuation">(</span>weights_path<span class="token punctuation">)</span><span class="token punctuation">)</span> torch<span class="token punctuation">.</span>save<span class="token punctuation">(</span>net<span class="token punctuation">.</span>state_dict<span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> weights_path<span class="token punctuation">)</span> best_acc <span class="token operator">=</span> acc <span class="token keyword">continue</span><span class="token comment">#定期保存模型。当前epoch是SAVE_EPOCH的倍数</span><span class="token keyword">if</span> <span class="token keyword">not</span> epoch <span class="token operator">%</span> settings<span class="token punctuation">.</span>SAVE_EPOCH<span class="token punctuation">:</span> weights_path <span class="token operator">=</span> checkpoint_path<span class="token punctuation">.</span><span class="token builtin">format</span><span class="token punctuation">(</span>net<span class="token operator">=</span>args<span class="token punctuation">.</span>net<span class="token punctuation">,</span> epoch<span class="token operator">=</span>epoch<span class="token punctuation">,</span> <span class="token builtin">type</span><span class="token operator">=</span><span class="token string">'regular'</span><span class="token punctuation">)</span> <span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">'saving weights file to {}'</span><span class="token punctuation">.</span><span class="token builtin">format</span><span class="token punctuation">(</span>weights_path<span class="token punctuation">)</span><span class="token punctuation">)</span> torch<span class="token punctuation">.</span>save<span class="token punctuation">(</span>net<span class="token punctuation">.</span>state_dict<span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> weights_path<span class="token punctuation">)</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="8-加载模型"><a href="#8-加载模型" class="headerlink" title="8. 加载模型"></a>8. 加载模型</h2><p>在需要时，可以随时加载已保存的模型权重继续使用</p><pre class="line-numbers language-python" data-language="python"><code class="language-python">net <span class="token operator">=</span> vgg11<span class="token punctuation">(</span><span class="token punctuation">)</span>net<span class="token punctuation">.</span>load_state_dict<span class="token punctuation">(</span>torch<span class="token punctuation">.</span>load<span class="token punctuation">(</span><span class="token string">'model.pth'</span><span class="token punctuation">)</span><span class="token punctuation">)</span>net<span class="token punctuation">.</span><span class="token builtin">eval</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span></span></code></pre>]]></content>
<categories>
<category> 深度学习 </category>
</categories>
<tags>
<tag> 深度学习基础 </tag>
<tag> 模型训练 </tag>
</tags>
</entry>
<entry>
<title>Notion常用快捷键</title>
<link href="/2024/06/02/notion-chang-yong-kuai-jie-jian/"/>
<url>/2024/06/02/notion-chang-yong-kuai-jie-jian/</url>
<content type="html"><![CDATA[<h2 id="常用Notion快捷键-amp-命令"><a href="#常用Notion快捷键-amp-命令" class="headerlink" title="常用Notion快捷键&命令"></a><strong>常用Notion快捷键&命令</strong></h2><p>以下是Notion中最常用的一些快捷键和命令，建议熟练掌握：</p><table><thead><tr><th>Windows快捷键</th><th>功能</th><th>Mac快捷键</th></tr></thead><tbody><tr><td>ctrl + N</td><td>新建页面</td><td>⌘ + N</td></tr><tr><td>ctrl + shift + U</td><td>跳转到导航条的第一个页面</td><td>⌘ + shift + U</td></tr><tr><td>shift + enter</td><td>表格插入新行（非编辑模式下才有效）</td><td>shift + enter</td></tr><tr><td>ctrl + /</td><td>改变内容块（Block）的Type类型</td><td>⌘ + /</td></tr><tr><td>/into[type]</td><td>例子：在block的右侧输入/intopage，可将内容块的类型改为Page</td><td>/into[type]</td></tr><tr><td>ctrl + \</td><td>收起或展开侧边栏</td><td>⌘ + \</td></tr><tr><td>ctrl + alt + t</td><td>折叠或展开笔记内容</td><td>⌘ + alt + t</td></tr><tr><td>ctrl + d</td><td>复制一个内容块Block</td><td>⌘ + d</td></tr><tr><td>ctrl + L</td><td>复制当前页面的链接</td><td>⌘ + L</td></tr><tr><td>ctrl + 鼠标左键ctrl + shift + N</td><td>在新窗口中打开笔记页</td><td>⌘ + 鼠标左键⌘ + shift + N</td></tr><tr><td>ctrl + R</td><td>页面卡住了？试一下刷新当前页面</td><td>⌘ + R</td></tr><tr><td>ctrl + alt + 9</td><td>把notionblock转换成page页面</td><td>⌘ + alt + 9</td></tr><tr><td>ctrl + shift + r</td><td>对Page页面链接重新命名</td><td>⌘ + shift + r</td></tr><tr><td>ctrl + P</td><td>查看最近浏览过的页面</td><td>⌘ + p</td></tr><tr><td>ctrl + [</td><td>回到上一个浏览的页面</td><td>⌘ + [</td></tr><tr><td>ctrl + ]</td><td>前进一个页面</td><td>⌘ + ]</td></tr><tr><td>ctrl + shift + L</td><td>切换黑色背景</td><td>⌘ + shift + L</td></tr><tr><td>windows键 + .windows键 + ;</td><td>插入emoji表情</td><td>control + ⌘+ space</td></tr></tbody></table><h2 id="文字编辑"><a href="#文字编辑" class="headerlink" title="文字编辑"></a><strong>文字编辑</strong></h2><table><thead><tr><th>Windows快捷键</th><th>功能</th><th>Mac快捷键</th></tr></thead><tbody><tr><td>ctrl + B</td><td>选中文字加粗</td><td>⌘ + B</td></tr><tr><td>ctrl + I</td><td>选中文字变斜体</td><td>⌘ + I</td></tr><tr><td>ctrl + U</td><td>选中文字加下划线</td><td>⌘ + U</td></tr><tr><td>ctrl + shift + S</td><td>选中文字加删除线</td><td>⌘ + shift + S</td></tr><tr><td>ctrl + K</td><td>选中文字添加链接</td><td>⌘ + K</td></tr><tr><td>ctrl + V</td><td>选中文字粘贴超链接</td><td>⌘ + V</td></tr><tr><td>ctrl + E</td><td>选中文字变成代码格式</td><td>⌘ + E</td></tr><tr><td>tab</td><td>为选中内容/block添加缩进</td><td>tab</td></tr><tr><td>shift + tab</td><td>为选中内容/block取消缩进</td><td>shift + tab</td></tr><tr><td>/turn</td><td>在block的开头或结尾插入。改变block的类型。</td><td>/turn</td></tr><tr><td>/color/color background</td><td>在block的开头或结尾插入。改变block的字体或背景颜色。</td><td>/color/color background</td></tr><tr><td>/default</td><td>在block的开头或结尾插入。移除字体或背景颜色。</td><td>/default</td></tr></tbody></table><h2 id="新建内容"><a href="#新建内容" class="headerlink" title="新建内容"></a><strong>新建内容</strong></h2><table><thead><tr><th>Windows快捷键</th><th>功能</th><th>Mac快捷键</th></tr></thead><tbody><tr><td>enter</td><td>在block内插入新行</td><td>enter</td></tr><tr><td>shift + enter</td><td>插入一个新的文字block</td><td>shift + enter</td></tr><tr><td>ctrl + shift + M</td><td>新建一个评论</td><td>⌘ + shift + M</td></tr><tr><td>—</td><td>在新行输入—可创建分隔符</td><td>—</td></tr><tr><td>ctrl + shift + 0</td><td>新建文字内容</td><td>⌘ + option + 0</td></tr><tr><td>ctrl + shift + 1</td><td>新建H1标题</td><td>⌘ + option + 1</td></tr><tr><td>ctrl + shift + 2</td><td>新建H2标题</td><td>⌘ + option + 2</td></tr><tr><td>ctrl + shift + 3</td><td>新建H3标题</td><td>⌘ + option + 3</td></tr><tr><td>ctrl + shift + 4</td><td>新建勾选框</td><td>⌘ + option + 4</td></tr><tr><td>ctrl + shift + 5</td><td>新建无序列表</td><td>⌘ + option + 5</td></tr><tr><td>ctrl + shift + 6</td><td>新建有序列表</td><td>⌘ + option + 6</td></tr><tr><td>ctrl + shift + 7</td><td>新建折叠列表（Toggle List）</td><td>⌘ + option + 7</td></tr><tr><td>ctrl + shift + 8</td><td>新建代码块</td><td>⌘ + option + 8</td></tr><tr><td>ctrl + shift + 9</td><td>新建页面，或将当前行内容转换为页面</td><td>⌘ + option + 9</td></tr><tr><td>ctrl + +</td><td>放大</td><td>⌘ + +</td></tr><tr><td>ctrl + –</td><td>缩小</td><td>⌘ + –</td></tr><tr><td>ctrl + shift + U</td><td>返回导航条上一级页面</td><td>⌘ + shift + U</td></tr><tr><td>alt</td><td>按住并拖放，克隆页面中的任意内容</td><td>option</td></tr></tbody></table><h2 id="移动或编辑内容块（Block）"><a href="#移动或编辑内容块（Block）" class="headerlink" title="移动或编辑内容块（Block）"></a><strong>移动或编辑内容块（Block）</strong></h2><table><thead><tr><th>Windows快捷键</th><th>功能</th><th>Mac快捷键</th></tr></thead><tbody><tr><td>esc</td><td>选中当前正在编辑的Block再按一次取消选中</td><td>esc</td></tr><tr><td>ctrl + a</td><td>全选当前Block的内容</td><td>⌘ + a</td></tr><tr><td>space</td><td>打开当前选中的图片</td><td>space</td></tr><tr><td>方向键</td><td>选择不同的block</td><td>方向键</td></tr><tr><td>shift + ↑/↓</td><td>选中光标前方或后方内容</td><td>shift + ↑/↓</td></tr><tr><td>alt + shift + click</td><td>同时选中多个block</td><td>⌘ + shift + click</td></tr><tr><td>shift + click</td><td>选中另一个block，并将它与当前block之间的block全部选中</td><td>shift + click</td></tr><tr><td>Backspace/Delete</td><td>删除选中的block</td><td>Backspace/Delete</td></tr><tr><td>ctrl + D</td><td>复制当前或选中的block</td><td>⌘ + D</td></tr><tr><td>ctrl + /</td><td>修改block样式，输入color、turn into可以修改block的颜色和类型</td><td>⌘ + /</td></tr><tr><td>ctrl + shift + 方向键</td><td>移动block的位置</td><td>⌘ + shift + 方向键</td></tr><tr><td>ctrl + alt + T</td><td>折叠或展开折叠块(Toggle List)</td><td>⌘ + option + T</td></tr><tr><td>ctrl + shift + H</td><td>高亮选中文字</td><td>⌘ + shift + H</td></tr><tr><td>ctrl + enter</td><td>多功能热键：打开一个页面链接勾选/取消勾选展开/折叠当前折叠块全屏显示图片</td><td>⌘ + enter</td></tr></tbody></table><h2 id="“-”命令：提示和提醒"><a href="#“-”命令：提示和提醒" class="headerlink" title="“@”命令：提示和提醒"></a><strong>“@”命令：提示和提醒</strong></h2><table><thead><tr><th>命令</th><th>功能</th></tr></thead><tbody><tr><td>@[member’s name]</td><td>输入@和团队成员的名字，可以提醒或通知该成员</td></tr><tr><td>@[page’s name]</td><td>输入@和页面标题，可以插入该页面的链接</td></tr><tr><td>@[date]</td><td>输入@和任意格式的日期，或’today’/’yesterday’/’tomorrow’等，在输入截止日时很有用</td></tr><tr><td>@remind[date]</td><td>输入@remind和任意格式时间，你可以在该指定时间收到notion的通知</td></tr></tbody></table><p><strong>注：如果你只想打出@这个符号，按esc可以取消@菜单</strong></p><h2 id="“-“命令：页面链接"><a href="#“-“命令：页面链接" class="headerlink" title="“[[“命令：页面链接"></a><strong>“[[“命令：页面链接</strong></h2><table><thead><tr><th>命令</th><th>功能</th></tr></thead><tbody><tr><td>[[</td><td>输入[[和另一个页面的标题，可以插入该页面的链接</td></tr><tr><td>[[</td><td>输入[[和你想要的任意名字，配合方向键点击+ Add new sub-page 可以在当前页面新建一个sub-page</td></tr><tr><td>[[</td><td>输入[[和你想要的任意名字，配合方向键点击↗︎ Add new page in…可以在其他页面或database新建一个sub-page</td></tr></tbody></table><h2 id="“-”命令：新建页面"><a href="#“-”命令：新建页面" class="headerlink" title="“+”命令：新建页面"></a><strong>“+”命令：新建页面</strong></h2><table><thead><tr><th>命令</th><th>功能</th></tr></thead><tbody><tr><td>+</td><td>输入+和任意名称，配合方向键点击+ Add new sub-page 可以在当前页面新建一个sub-page</td></tr><tr><td>+</td><td>输入+和任意名称，配合方向键点击↗︎ Add new page in…可以在其他页面或database新建一个sub-page</td></tr><tr><td>+</td><td>输入+和另一个页面的标题，可以插入该页面的链接</td></tr></tbody></table><p><strong>注意：[[命令侧重于插入页面链接功能，+命令侧重新建页面功能。</strong></p><h2 id="“-x2F-“命令"><a href="#“-x2F-“命令" class="headerlink" title="“/“命令"></a><strong>“/“命令</strong></h2><h3 id="基础”-x2F-“命令"><a href="#基础”-x2F-“命令" class="headerlink" title="基础”/“命令"></a><strong>基础”/“命令</strong></h3><table><thead><tr><th>命令</th><th>功能</th></tr></thead><tbody><tr><td>/</td><td>输入/命令会弹出Block菜单，配合方向键可新建任意类型的内容块</td></tr><tr><td>/text 或 /plain</td><td>新建文字内容块text block</td></tr><tr><td>/page</td><td>新建页面page（回车后自动打开该页面）</td></tr><tr><td>/bullet</td><td>新建无序列表</td></tr><tr><td>/num</td><td>新建有序列表</td></tr><tr><td>/todo</td><td>新建待办事项和复选框</td></tr><tr><td>/toggle</td><td>新建折叠内容块（可折叠/展开）</td></tr><tr><td>/div</td><td>新建分隔符</td></tr><tr><td>/quote</td><td>新建引用内容块</td></tr><tr><td>/h1 或 /#</td><td>新建h1标题</td></tr><tr><td>/h2 或 /##</td><td>新建h2标题</td></tr><tr><td>/h3 或 /###</td><td>新建h3标题</td></tr><tr><td>/link</td><td>新建页面链接page link</td></tr><tr><td>esc</td><td>如果只想输入/，可以按esc退出菜单</td></tr></tbody></table><h3 id="行内”-x2F-“命令"><a href="#行内”-x2F-“命令" class="headerlink" title="行内”/“命令"></a><strong>行内”/“命令</strong></h3><table><thead><tr><th>命令</th><th>功能</th></tr></thead><tbody><tr><td>/mention</td><td>提示团队中的某位成员，或者提示某个页面</td></tr><tr><td>/date 或 /reminder</td><td>添加时间戳或时间提示</td></tr><tr><td>/equation</td><td>添加TeX格式的公式</td></tr><tr><td>/emoji</td><td>添加emoji表情</td></tr></tbody></table><h3 id="数据视图”-x2F-“命令"><a href="#数据视图”-x2F-“命令" class="headerlink" title="数据视图”/“命令"></a><strong>数据视图”/“命令</strong></h3><table><thead><tr><th>命令</th><th>功能</th></tr></thead><tbody><tr><td>/table-inline</td><td>新建行内普通表格</td></tr><tr><td>/database-inline</td><td>新建行内Database数据库表格</td></tr><tr><td>/board-inline</td><td>新建行内卡片（board）</td></tr><tr><td>/calendar-inline</td><td>新建行内日历</td></tr><tr><td>/list-inline</td><td>新建行内页面列表（list）</td></tr><tr><td>/gallery-inline</td><td>新建行内画廊数据表（gallery）</td></tr><tr><td>/timeline-inline</td><td>新建时间线数据表</td></tr><tr><td>/linked</td><td>在当前页面引用database数据表</td></tr></tbody></table><p><strong>注：以上命令中的-inline都可以替换为-full，替换后新建的对象都以Page的形式打开。如: /table-full, /board-full</strong></p><h3 id="媒体”-x2F-“命令"><a href="#媒体”-x2F-“命令" class="headerlink" title="媒体”/“命令"></a><strong>媒体”/“命令</strong></h3><table><thead><tr><th>命令</th><th>功能</th></tr></thead><tbody><tr><td>/image</td><td>插入图片</td></tr><tr><td>/pdf</td><td>插入pdf</td></tr><tr><td>/book</td><td>插入网页链接并保存为书签</td></tr><tr><td>/video</td><td>插入视频</td></tr><tr><td>/audio</td><td>插入音频</td></tr><tr><td>/code</td><td>插入代码块</td></tr><tr><td>/file</td><td>插入文档</td></tr><tr><td>/embed</td><td>插入各种外部文件（500+种格式可选）</td></tr></tbody></table><h3 id="高级”-x2F-“命令"><a href="#高级”-x2F-“命令" class="headerlink" title="高级”/“命令"></a><strong>高级”/“命令</strong></h3><table><thead><tr><th>命令</th><th>功能</th></tr></thead><tbody><tr><td>/comment</td><td>在当前block插入评论</td></tr><tr><td>/duplicate</td><td>复制当前block</td></tr><tr><td>/moveto</td><td>将当前block移动到其他页面</td></tr><tr><td>/delete</td><td>删除当前块</td></tr><tr><td>/toc</td><td>插入目录</td></tr><tr><td>/button 或 /template</td><td>插入按钮</td></tr><tr><td>/bread</td><td>插入面包屑导航条</td></tr><tr><td>/math 或 /latex</td><td>插入数学公式</td></tr></tbody></table><h2 id="Markdown-语法"><a href="#Markdown-语法" class="headerlink" title="Markdown 语法"></a><strong>Markdown 语法</strong></h2><h3 id="使用Markdown编辑文本格式"><a href="#使用Markdown编辑文本格式" class="headerlink" title="使用Markdown编辑文本格式"></a><strong>使用Markdown编辑文本格式</strong></h3><table><thead><tr><th>命令</th><th>功能</th></tr></thead><tbody><tr><td>** 内容 **</td><td>加粗，只适用于Text内容块</td></tr><tr><td>*内容* 或 _内容_</td><td>斜体，只适用于Text内容块</td></tr><tr><td>`内容`</td><td>把内容转换为高亮代码格式，只适用于Text内容块</td></tr><tr><td>~内容~</td><td>给内容增加删除线，只适用于Text内容块</td></tr></tbody></table><h3 id="使用Markdown插入新内容块"><a href="#使用Markdown插入新内容块" class="headerlink" title="使用Markdown插入新内容块"></a><strong>使用Markdown插入新内容块</strong></h3><table><thead><tr><th>命令</th><th>功能</th></tr></thead><tbody><tr><td>– + space</td><td>插入无序列表</td></tr><tr><td>[] + space</td><td>插入复选框</td></tr><tr><td>1. 或 a. 或 i. + space</td><td>插入有序列表</td></tr><tr><td># + space</td><td>插入h1标题</td></tr><tr><td>## + space</td><td>插入h2标题</td></tr><tr><td>### + space</td><td>插入h3标题</td></tr><tr><td>> + space</td><td>插入折叠内容块（Toggle）</td></tr><tr><td>” + space</td><td>插入引用内容块（Quote）</td></tr></tbody></table>]]></content>
<categories>
<category> 工具 </category>
</categories>
<tags>
<tag> 快捷键 </tag>
<tag> 效率提升 </tag>
<tag> Notion </tag>
</tags>
</entry>
<entry>
<title>Ubuntu22.04安装OpenFOAM_v2212</title>
<link href="/2024/05/31/ubuntu22-04-an-zhuang-openfoam-v2212/"/>
<url>/2024/05/31/ubuntu22-04-an-zhuang-openfoam-v2212/</url>
<content type="html"><![CDATA[<h2 id="0、环境准备"><a href="#0、环境准备" class="headerlink" title="0、环境准备"></a>0、环境准备</h2><p>该并行应用程序需要使用 <code>openmpi</code>，因此需要事先安装<code>openmpi</code>。MPI 的安装方式可以查看之前的<a href="https://antoniozc666.github.io/2024/04/02/nemo-hai-yang-mo-xing-de-an-zhuang-da-jian-yu-yun-xing/">博客</a>。</p><p>需要实现在系统上安装以下依赖项：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token function">sudo</span> <span class="token function">apt-get</span> <span class="token function">install</span> build-essential autoconf autotools-dev cmake <span class="token function">gawk</span> gnuplot<span class="token function">sudo</span> <span class="token function">apt-get</span> <span class="token function">install</span> flex libfl-dev libreadline-dev zlib1g-dev openmpi-bin libopenmpi-dev mpi-default-bin mpi-default-dev<span class="token function">sudo</span> <span class="token function">apt-get</span> <span class="token function">install</span> libgmp-dev libmpfr-dev libmpc-dev<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span></span></code></pre><p>要检查可用的系统版本，请使用 <code>apt-cache show</code> 命令。例如：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token function">apt-cache</span> show libopenmpi-dev<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>如果要使用系统组件，还需要安装以下组件：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token function">apt-get</span> <span class="token function">install</span> libfftw3-dev libscotch-dev libptscotch-dev libboost-system-dev libboost-thread-dev libcgal-dev<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>其他的软件要求如下：</p><p><img src="/2024/05/31/ubuntu22-04-an-zhuang-openfoam-v2212/openfoam%E7%B3%BB%E7%BB%9F%E8%A6%81%E6%B1%82.png"></p><h2 id="一、安装步骤"><a href="#一、安装步骤" class="headerlink" title="一、安装步骤"></a>一、安装步骤</h2><p>OpenFOAM有两种版本：一个是商业版本，版本编号为从1开始的数字（如：OpenFOAM v11）；一个公益开源版本，版本编号为年份加月份（如：OpenFOAM v2212）。</p><h3 id="1、下载源码"><a href="#1、下载源码" class="headerlink" title="1、下载源码"></a>1、下载源码</h3><p>从<a href="https://dl.openfoam.com/source/v2212/">网站</a>上下载<code>OpenFOAM v2212</code>和<code>ThirdParty v2212</code>源代码，并将其上传到服务器。我存放的路径为：<code>/home/czhang/openfoam</code>。进入该存放路径，解压缩两个源代码压缩包。</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token function">tar</span> -zxvf OpenFOAM-v2212.tgz<span class="token function">tar</span> -zxvf ThirdParty-v2212.tgz<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><h3 id="2、设置环境变量"><a href="#2、设置环境变量" class="headerlink" title="2、设置环境变量"></a>2、设置环境变量</h3><p>在构建之前，要先满足系统要求，并获取正确的 OpenFOAM 环境。例如，对于 OpenFOAM-v2212 版本：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token builtin class-name">source</span> <span class="token operator"><</span>installation path<span class="token operator">></span>/OpenFOAM-v2212/etc/bashrc<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>在我这里，我安装在 <code>~/openfoam</code> 目录下，所以我这里是：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token builtin class-name">source</span> ~/openfoam/OpenFOAM-v2212/etc/bashrc<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p><strong>建议：</strong>将这句命令添加到用户根目录下的 <code>.bashrc/.zshrc</code>文件中</p><h3 id="3、编译OpenFOAM"><a href="#3、编译OpenFOAM" class="headerlink" title="3、编译OpenFOAM"></a>3、编译OpenFOAM</h3><p>进入OpenFOAM所在的目录进行操作：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token builtin class-name">cd</span> /home/czhang/openfoam/OpenFOAM-v2212<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>测试系统就绪情况：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">foamSystemCheck<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>新建一个shell命令窗口，切换到 OpenFOAM 主目录 （$WM_PROJECT_DIR）。如果此操作失败，则环境配置不正确。</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">foam<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>编译openfoam：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">./Allwmake -j -s -q -l<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>该命令使用所有内核 （-j），缩减输出 （-s， -silent）、队列 （-q， -queue） ，将编译信息一起输出到日志文件 （-l， -log） <code>log.linux64GccDPInt32Opt</code> 供以后检查。</p><h3 id="4、编译后检验"><a href="#4、编译后检验" class="headerlink" title="4、编译后检验"></a>4、编译后检验</h3><p>打开一个新的 shell 窗口并获取 OpenFOAM 环境。</p><p>通过运行以下命令来验证生成：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">foamInstallationTest<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>如果报错显示 <code>icoFoam</code>没有找到，则使用<code>Allwmake</code>去掉参数 <code>-q</code>重新编译。</p><p>之后测试任何给定的教程案例，例如：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">foamTestTutorial -full incompressible/simpleFoam/pitzDaily<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p><img src="/2024/05/31/ubuntu22-04-an-zhuang-openfoam-v2212/%E6%B5%8B%E8%AF%95%E6%95%99%E7%A8%8B%E6%A1%88%E4%BE%8B.png"></p><p>手动测试教程案例：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token comment"># Create the user "run" directory:</span><span class="token function">mkdir</span> -p <span class="token string">"<span class="token variable">$FOAM_RUN</span>"</span><span class="token comment"># Change to the user "run" directory:</span>run<span class="token comment"># Copy tutorial</span><span class="token function">cp</span> -r <span class="token string">"<span class="token variable">$FOAM_TUTORIALS</span>"</span>/incompressible/simpleFoam/pitzDaily ./<span class="token comment"># Run the tutorial</span><span class="token builtin class-name">cd</span> pitzDaily <span class="token operator">&&</span> blockMesh <span class="token operator">&&</span> simpleFoam<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p><img src="/2024/05/31/ubuntu22-04-an-zhuang-openfoam-v2212/%E6%89%8B%E5%8A%A8%E6%B5%8B%E8%AF%95%E7%94%A8%E4%BE%8B%E9%83%A8%E5%88%86%E7%BB%93%E6%9E%9C%E5%B1%95%E7%A4%BA.png"></p><h2 id="二、安装第三方部分"><a href="#二、安装第三方部分" class="headerlink" title="二、安装第三方部分"></a>二、安装第三方部分</h2><h3 id="1、环境准备"><a href="#1、环境准备" class="headerlink" title="1、环境准备"></a>1、环境准备</h3><p>将第三方部分所需的依赖项引入系统的一种快速方法是使用 paraview 开发包：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token function">sudo</span> <span class="token function">apt</span> <span class="token function">install</span> paraview-dev<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>这是一个软件包，可以寻求系统管理员安装。</p><p>同时也要安装以下依赖：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token function">sudo</span> <span class="token function">apt</span> <span class="token function">install</span> cmake qtbase5-dev qttools5-dev qttools5-dev-tools libqt5opengl5-dev libqt5x11extras5-dev libxt-dev<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>可以用之前的 <code>apt-cache show</code>命令查看系统是否拥有。</p><h3 id="2、构建第三方部分"><a href="#2、构建第三方部分" class="headerlink" title="2、构建第三方部分"></a>2、构建第三方部分</h3><p>切换目录到第三方部分的目录：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token builtin class-name">cd</span> /home/czhang/openfoam/ThirdParty-v2212<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>运行命令：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">./Allwmake -j -s -q -l<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>期间可能会报错显示部分库找不到，如：gmp等，可以安装相应的依赖库：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token function">sudo</span> <span class="token function">apt-get</span> <span class="token function">install</span> libmpfr-dev, libgmp-dev, libboost-all-dev<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><h2 id="三、测试安装结果"><a href="#三、测试安装结果" class="headerlink" title="三、测试安装结果"></a>三、测试安装结果</h2><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">foamVersion<span class="token comment"># icoFoam</span>blockMeshsimpleFoam<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span></span></code></pre><p>若输出结果均无报错则安装成功，在运行求解器（如icoFoam，simpleFoam等）之前需要先用blockMesh划分网格。</p><h2 id="四、案例测试"><a href="#四、案例测试" class="headerlink" title="四、案例测试"></a>四、案例测试</h2><p>运行命令 <code>run</code>跳转到测试运行目录，运行命令：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token function">cp</span> -r <span class="token string">"<span class="token variable">$FOAM_TUTORIALS</span>"</span>/incompressible/icoFoam/cavity ./<span class="token builtin class-name">cd</span> cavity<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><p>将tutorials中的cavity测试案例复制到run目录下，并进入cavity文件夹中。</p><p>在system文件夹中有一些运行控制文件，可通过修改这些文件中的值来调整运行参数</p><p><img src="/2024/05/31/ubuntu22-04-an-zhuang-openfoam-v2212/system%E7%9B%AE%E5%BD%95%E7%BB%93%E6%9E%84.png"></p><p>运行命令：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">blockMeshicoFoam<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><p>在运行求解器之前需要运行blockMesh划分网格。</p><p>如果要使用mpi进行并行运行，则需要先使用OpenFOAM的并行工具来分割计算域</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">decomposePar<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>该命令会自动创建像<code>processor0</code>这样的目录，分解了多少个计算域，就会产生多少个目录，之后要使用多少个线程运行。目录如图所示：</p><p><img src="/2024/05/31/ubuntu22-04-an-zhuang-openfoam-v2212/decomposePar%E7%BB%93%E6%9E%9C.png"></p><p>划分网格、分解计算域后，使用mpi并行运行分解器，要是用哪个分解器可在 <code>controlDict</code>中查看。</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">mpirun -np <span class="token number">9</span> icoFoam -parallel <span class="token operator">></span> icoFoamRun.log<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p><strong>Reference：</strong></p><p><a href="https://www.bilibili.com/list/watchlater?oid=207358298&bvid=BV1Vh411i7to&spm_id_from=333.1007.top_right_bar_window_view_later.content.click">OpenFOAM系列教程</a></p><p><a href="https://develop.openfoam.com/Development/openfoam/-/blob/master/doc/Build.md">OpenFOAM_v2212构建指南</a></p><p><a href="https://develop.openfoam.com/Development/ThirdParty-common/blob/develop/BUILD.md">第三方构建指南</a></p><p><a href="https://zhuanlan.zhihu.com/p/541266216">OpenFOAM安装教程1</a></p><p><a href="https://blog.csdn.net/qq_45682183/article/details/124945151">OpenFOAM安装教程2</a></p><p><a href="https://blog.csdn.net/AudrianaZhang/article/details/127043574">OpenFOAM安装教程3</a></p><p><a href="https://www.cfd-online.com/Forums/openfoam-installation/229950-icofoam-not-installed.html">icofoam未安装问题解决</a></p>]]></content>
<categories>
<category> 工作负载 </category>
</categories>
<tags>
<tag> 工作负载 </tag>
<tag> 环境搭建 </tag>
<tag> HPC </tag>
<tag> OpenFOAM </tag>
</tags>
</entry>
<entry>
<title>解决远程连接时VSCode与独立终端环境不一致问题</title>
<link href="/2024/05/30/jie-jue-yuan-cheng-lian-jie-shi-vscode-yu-du-li-zhong-duan-huan-jing-bu-yi-zhi-wen-ti/"/>
<url>/2024/05/30/jie-jue-yuan-cheng-lian-jie-shi-vscode-yu-du-li-zhong-duan-huan-jing-bu-yi-zhi-wen-ti/</url>
<content type="html"><</p><p>实际上这是由于<strong>vscode在远程服务器上有缓存</strong>，同时在关掉vscode后远程服务器上的 <strong><code>.vscode-server</code> 进程并没有停止</strong>成为了孤立进程。</p><h2 id="二、解决方法"><a href="#二、解决方法" class="headerlink" title="二、解决方法"></a>二、解决方法</h2><h3 id="1-查找vscode服务器进程"><a href="#1-查找vscode服务器进程" class="headerlink" title="1. 查找vscode服务器进程"></a>1. 查找vscode服务器进程</h3><p>使用 <code>ps</code> 命令列出进程并筛选与 VSCode 服务器相关的进程。通常，服务器进程的名称中将包含 <code>node</code> 或 <code>vscode-server</code> 。</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token function">ps</span> aux <span class="token operator">|</span> <span class="token function">grep</span> czhang/.vscode-server<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><h3 id="2-终止vscode服务器进程"><a href="#2-终止vscode服务器进程" class="headerlink" title="2. 终止vscode服务器进程"></a>2. 终止vscode服务器进程</h3><p>使用该 <code>kill</code> 命令终止进程。使用从上一步获取的进程 ID （PID）。</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token function">kill</span> -9 <span class="token operator"><</span>PID<span class="token operator"><span class="token file-descriptor important">1</span>></span> <span class="token operator"><</span>PID<span class="token operator"><span class="token file-descriptor important">2</span>></span> <span class="token punctuation">..</span>.<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><h3 id="3-删除vscode服务器目录"><a href="#3-删除vscode服务器目录" class="headerlink" title="3. 删除vscode服务器目录"></a>3. 删除vscode服务器目录</h3><p>VSCode 服务器目录通常位于主目录： <code>~/.vscode-server</code> 。使用 <code>rm</code> 命令删除 VSCode 服务器目录。这将强制 VSCode 在下次连接时重新安装服务器。</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token function">rm</span> -rf ~/.vscode-server<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><h3 id="4-重启vscode，重新连接到服务器"><a href="#4-重启vscode，重新连接到服务器" class="headerlink" title="4. 重启vscode，重新连接到服务器"></a>4. 重启vscode，重新连接到服务器</h3>]]></content>
<categories>
<category> 工具 </category>
</categories>
<tags>
<tag> IDE </tag>
<tag> vscode </tag>
<tag> SSH </tag>
<tag> debug </tag>
</tags>
</entry>
<entry>
<title>Linux环境下使用TPC-H测试MySQL教程</title>
<link href="/2024/05/19/linux-huan-jing-xia-shi-yong-tpc-h-ce-shi-mysql-jiao-cheng/"/>
<url>/2024/05/19/linux-huan-jing-xia-shi-yong-tpc-h-ce-shi-mysql-jiao-cheng/</url>
<content type="html"><![CDATA[<h2 id="TPC-H介绍"><a href="#TPC-H介绍" class="headerlink" title="TPC-H介绍"></a>TPC-H介绍</h2><p>TPC-H 是 TPC（Transaction Processing Performance Council）组织发布的一套数据库测试规范，同样的还有很多其他的规范，例如Hammer DB、BenchMarkSQL、Sysbench、YCSB等等一样，都是提供了一套标准，然后供市面上的相关产品来执行这套标准，根据测试结果，从侧面展示产品的性能。</p><p>从 <a href="https://www.tpc.org/">TPC 组织的官网</a> 可以了解到，TCP 提供了一系列基准，据我了解，数据库基准测试大致可以分为两类：<a href="https://en.wikipedia.org/wiki/Online_transaction_processing">OLTP</a>、<a href="https://en.wikipedia.org/wiki/Online_analytical_processing">OLAP</a>。OLTP 类型中最流行的就是 TPC-C 测试基准，而 OLAP 中比较流行的则是TPC-H，而我们这次选择的就是TPC-H基准测试 。</p><p>根据<a href="https://tpc.org/TPC_Documents_Current_Versions/pdf/tpc-h_v3.0.0.pdf">TPC-H的基准规范</a>可以知道，TPC-H 将海量数据存储在8张表中，并运行 22 个查询（Q1~Q22）来分析这些数据。其主要评价指标是各个查询的响应时间，即从提交查询到结果返回所需的时间，以及多个会话的吞吐量（每秒查询数量）。基准参考文档中介绍还介绍了，测试表与测试数据的详细信息，一些扩展数据以及执行规则等等，这是一份详细的规则清单以及说明。可以手动的根据基准规范文档来创建数据表、生成数据、执行查询语句。也可以使用TPC-H工具包来生成相应的数据表与数据，然后依次测试这22个查询。</p><p>接下来我会使用MySQL-8.0.36来测试TPC-H的相关基准。MySQL的安装请见之前的文章 <a href="https://antoniozc666.github.io/2024/04/17/linux-pu-tong-yong-hu-wu-root-quan-xian-an-zhuang-mysql-8-0-36/">Linux普通用户无root权限安装MySQL 8.0.36</a></p><h2 id="TPC-H安装包的获取"><a href="#TPC-H安装包的获取" class="headerlink" title="TPC-H安装包的获取"></a>TPC-H安装包的获取</h2><ol><li><p>首先进入官网：<a href="https://tpc.org/">TPC-Homepage</a></p></li><li><p>进入工具包下载页面</p><p><img src="/2024/05/19/linux-huan-jing-xia-shi-yong-tpc-h-ce-shi-mysql-jiao-cheng/TPC-H%E5%B7%A5%E5%85%B7%E5%8C%85%E8%8E%B7%E5%8F%961.png" alt="TPC-H工具包下载页面"></p></li><li><p>进入 TPC-H 下载页面</p><p><img src="/2024/05/19/linux-huan-jing-xia-shi-yong-tpc-h-ce-shi-mysql-jiao-cheng/TPC-H%E5%B7%A5%E5%85%B7%E5%8C%85%E8%8E%B7%E5%8F%962.png" alt="TPC-H下载页面"></p></li><li><p>填写相应信息与验证，获取下载地址</p><p><img src="/2024/05/19/linux-huan-jing-xia-shi-yong-tpc-h-ce-shi-mysql-jiao-cheng/TPC-H%E5%B7%A5%E5%85%B7%E5%8C%85%E8%8E%B7%E5%8F%963.png"></p></li><li><p>获取成功，从邮件中获取下载地址</p></li></ol><h2 id="TPC-H-工具包的使用与介绍"><a href="#TPC-H-工具包的使用与介绍" class="headerlink" title="TPC-H 工具包的使用与介绍"></a>TPC-H 工具包的使用与介绍</h2><p>查看工具包中的内容，了解 TPC-H 如何使用。</p><ul><li>安装包解压后，会有附带的 <code>specification.docx</code> 与 <code>specification.pdf</code> 这里面介绍了测试的相关标准，可以为手动测试提供参考。</li><li><code>TPC-H_Tools_v3.0.0/dbgen</code>目录下的 <code>READEME</code>文件，介绍了工具相关用途。</li></ul><p><img src="/2024/05/19/linux-huan-jing-xia-shi-yong-tpc-h-ce-shi-mysql-jiao-cheng/TPC-H-README.png" alt="TPC-H README文件目录"></p><h3 id="相关文件介绍"><a href="#相关文件介绍" class="headerlink" title="相关文件介绍"></a>相关文件介绍</h3><h4 id="dss-ddl"><a href="#dss-ddl" class="headerlink" title="dss.ddl"></a>dss.ddl</h4><p>该文件里面包含了 创建表的 8 条 SQL 语句。</p><h4 id="dss-ri"><a href="#dss-ri" class="headerlink" title="dss.ri"></a>dss.ri</h4><p>这里是创建表约束的 SQL 语句，例如主键与外键。</p><h4 id="x2F-queries-文件夹"><a href="#x2F-queries-文件夹" class="headerlink" title="/queries 文件夹"></a>/queries 文件夹</h4><p>该文件夹下面是 22 条查询 SQL。</p><h4 id="上一层的-x2F-ref-data-文件夹"><a href="#上一层的-x2F-ref-data-文件夹" class="headerlink" title="上一层的 /ref_data 文件夹"></a>上一层的 /ref_data 文件夹</h4><p>该文件夹里面存放了，填充数据表所需要的数据。</p><h4 id="dbgen-与-qgen"><a href="#dbgen-与-qgen" class="headerlink" title="dbgen 与 qgen"></a>dbgen 与 qgen</h4><p><strong>dbgen</strong> 是用来生成与填充 符合基准的数据表的程序，来帮助我们简单的构建符合要求的数据表与数据。</p><p><strong>qgen</strong> 是基于基准的查询程序，来帮助我们构建一个简单的基准实现。</p><p>以上两个可执行文件，均需要编译生成。</p><h2 id="TPC-H工具包的编译与安装"><a href="#TPC-H工具包的编译与安装" class="headerlink" title="TPC-H工具包的编译与安装"></a>TPC-H工具包的编译与安装</h2><h3 id="准备与解压"><a href="#准备与解压" class="headerlink" title="准备与解压"></a>准备与解压</h3><p>将下载得到的安装包上传到服务器上，重命名后解压：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token function">unzip</span> tpc-h.zip<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>将文件夹放到你自己想要的位置</p><h3 id="修改部分文件"><a href="#修改部分文件" class="headerlink" title="修改部分文件"></a>修改部分文件</h3><ul><li><strong>后续大部分的 修改、编译、执行等操作都在</strong> <code>mysql-tpc-h/dbgen</code> <strong>目录下完成</strong></li></ul><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token builtin class-name">cd</span> mysql-tpc-h/dbgen<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><h3 id="修改makefile文件"><a href="#修改makefile文件" class="headerlink" title="修改makefile文件"></a>修改makefile文件</h3><p>该文件约束了 编译 后可执行文件的部分条件以及需要的依赖。</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token function">cp</span> makefile.suite makefile<span class="token function">vim</span> makefile<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token comment"># 修改 103 109 110 111 这四行的内容</span>CC <span class="token operator">=</span> gcc<span class="token comment"># Current values for DATABASE are: INFORMIX, DB2, TDAT (Teradata)</span><span class="token comment"># SQLSERVER, SYBASE, ORACLE, VECTORWISE</span><span class="token comment"># Current values for MACHINE are: ATT, DOS, HP, IBM, ICL, MVS, </span><span class="token comment"># SGI, SUN, U2200, VMS, LINUX, WIN32 </span><span class="token comment"># Current values for WORKLOAD are: TPCH</span><span class="token comment"># 这儿的 DATABASE 字段 指明了一些常用的商业数据库 如果写 MYSQL 需要在 tpcd.h 文件中添加部分宏定义</span><span class="token assign-left variable">DATABASE</span><span class="token operator">=</span> MYSQLMACHINE <span class="token operator">=</span> LINUXWORKLOAD <span class="token operator">=</span> TPCH<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h3 id="修改-tpcd-h-文件"><a href="#修改-tpcd-h-文件" class="headerlink" title="修改 tpcd.h 文件"></a>修改 tpcd.h 文件</h3><p>在该文件中添加以下信息：</p><pre class="line-numbers language-c" data-language="c"><code class="language-c"><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">ifdef</span> <span class="token expression">MYSQL</span></span><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">define</span> <span class="token macro-name">GEN_QUERY_PLAN</span> <span class="token string">""</span></span><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">define</span> <span class="token macro-name">START_TRAN</span> <span class="token string">"START TRANSACTION"</span></span><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">define</span> <span class="token macro-name">END_TRAN</span> <span class="token string">"COMMIT"</span></span><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">define</span> <span class="token macro-name">SET_OUTPUT</span> <span class="token string">""</span></span><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">define</span> <span class="token macro-name">SET_ROWCOUNT</span> <span class="token string">"limit %d;\n"</span></span><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">define</span> <span class="token macro-name">SET_DBASE</span> <span class="token string">"use %s;\n"</span></span><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">endif</span></span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h3 id="编译"><a href="#编译" class="headerlink" title="编译"></a>编译</h3><p>修改了上述文件后 ，我们直接在 <code>/dbgen</code> 目录下使用 <code>make</code> 命令，来生成可执行文件 <code>dbgen</code> 和 <code>qgen</code>。</p><h2 id="TPC-H工具包数据的生成、导入与查询"><a href="#TPC-H工具包数据的生成、导入与查询" class="headerlink" title="TPC-H工具包数据的生成、导入与查询"></a>TPC-H工具包数据的生成、导入与查询</h2><h3 id="生成-lt-table-gt-tbl-数据文件"><a href="#生成-lt-table-gt-tbl-数据文件" class="headerlink" title="生成 <table>.tbl 数据文件"></a>生成 <code><table>.tbl</code> 数据文件</h3><p>可以使用 <code>./dbgen -h</code> 命令查看，也可以查看 <code>README</code> 中对 <code>dbgen</code> 的相关介绍。</p><p><img src="/2024/05/19/linux-huan-jing-xia-shi-yong-tpc-h-ce-shi-mysql-jiao-cheng/dbgen%E5%B8%AE%E5%8A%A9%E4%BF%A1%E6%81%AF.png" alt="dbgen帮助信息"></p><p>使用命令生成符合基准的8张表与相应的数据。由介绍可知， <code>-s</code> 后面是<strong>数据量的大小</strong>，若为 <strong>10</strong> 则生成 <strong>10GB</strong> 数据，若为<strong>100</strong>则生成<strong>100GB</strong>的数据。</p><p>-V ：显示进度消息</p><p>-f ：覆盖原始数据</p><p>-s ： 生成数据的总体规模</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token comment"># 生成数据</span>./dbgen -vf -s <span class="token number">100</span><span class="token comment"># 查看生成的数据</span><span class="token function">ls</span> *.tbl<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span></span></code></pre><h3 id="导入构建脚本文件"><a href="#导入构建脚本文件" class="headerlink" title="导入构建脚本文件"></a>导入构建脚本文件</h3><p>编译之后有<code>dss.ddl</code>和<code>dss.ri</code>两个脚本，dss.ddl是建表脚本，dss.ri脚本是建立主键外键关联关系。</p><p>因为TPC-H benchmark本身不支持MySQL；并且由于MySQL的表名、库名等<strong>默认</strong>都是<strong>严格区分大小写的</strong>，而 <code>dss.ddl</code>（建表脚本）与 <code>dss.ri</code>（表约束脚本）中使用的都是<strong>大写的数据库名与表名</strong>，但是提供的 22 条查询语句又使用的<strong>小写的表名</strong>。所以需要先修改这两个脚本。</p><h4 id="修改-dss-dll"><a href="#修改-dss-dll" class="headerlink" title="修改 dss.dll"></a>修改 <code>dss.dll</code></h4><p>在文件开头添加以下语句：</p><pre class="line-numbers language-sql" data-language="sql"><code class="language-sql"><span class="token keyword">DROP</span> <span class="token keyword">DATABASE</span> <span class="token keyword">IF</span> <span class="token keyword">EXISTS</span> tpch<span class="token punctuation">;</span><span class="token keyword">CREATE</span> <span class="token keyword">DATABASE</span> tpch<span class="token punctuation">;</span><span class="token keyword">USE</span> tpch<span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span></span></code></pre><h4 id="修改-dss-ri"><a href="#修改-dss-ri" class="headerlink" title="修改 dss.ri"></a>修改 <code>dss.ri</code></h4><p>可先备份一份，之后将内容修改为以下内容：</p><pre class="line-numbers language-sql" data-language="sql"><code class="language-sql"><span class="token comment">-- Sccsid: @(#)dss.ri 2.1.8.1</span><span class="token comment">-- tpch Benchmark Version 8.0</span><span class="token comment">-- CONNECT TO tpch;</span><span class="token keyword">use</span> tpch<span class="token punctuation">;</span><span class="token comment">-- ALTER TABLE tpch.REGION DROP PRIMARY KEY;</span><span class="token comment">-- ALTER TABLE tpch.NATION DROP PRIMARY KEY;</span><span class="token comment">-- ALTER TABLE tpch.PART DROP PRIMARY KEY;</span><span class="token comment">-- ALTER TABLE tpch.SUPPLIER DROP PRIMARY KEY;</span><span class="token comment">-- ALTER TABLE tpch.PARTSUPP DROP PRIMARY KEY;</span><span class="token comment">-- ALTER TABLE tpch.ORDERS DROP PRIMARY KEY;</span><span class="token comment">-- ALTER TABLE tpch.LINEITEM DROP PRIMARY KEY;</span><span class="token comment">-- ALTER TABLE tpch.CUSTOMER DROP PRIMARY KEY;</span><span class="token comment">-- For table REGION</span><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tpch<span class="token punctuation">.</span>REGION<span class="token keyword">ADD</span> <span class="token keyword">PRIMARY</span> <span class="token keyword">KEY</span> <span class="token punctuation">(</span>R_REGIONKEY<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">-- For table NATION</span><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tpch<span class="token punctuation">.</span>NATION<span class="token keyword">ADD</span> <span class="token keyword">PRIMARY</span> <span class="token keyword">KEY</span> <span class="token punctuation">(</span>N_NATIONKEY<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tpch<span class="token punctuation">.</span>NATION<span class="token comment">-- ADD FOREIGN KEY NATION_FK1 (N_REGIONKEY) references tpch.REGION;</span><span class="token keyword">ADD</span> <span class="token keyword">FOREIGN</span> <span class="token keyword">KEY</span> NATION_FK1 <span class="token punctuation">(</span>N_REGIONKEY<span class="token punctuation">)</span> <span class="token keyword">references</span> tpch<span class="token punctuation">.</span>REGION<span class="token punctuation">(</span>R_REGIONKEY<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token keyword">COMMIT</span> <span class="token keyword">WORK</span><span class="token punctuation">;</span><span class="token comment">-- For table PART</span><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tpch<span class="token punctuation">.</span>PART<span class="token keyword">ADD</span> <span class="token keyword">PRIMARY</span> <span class="token keyword">KEY</span> <span class="token punctuation">(</span>P_PARTKEY<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token keyword">COMMIT</span> <span class="token keyword">WORK</span><span class="token punctuation">;</span><span class="token comment">-- For table SUPPLIER</span><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tpch<span class="token punctuation">.</span>SUPPLIER<span class="token keyword">ADD</span> <span class="token keyword">PRIMARY</span> <span class="token keyword">KEY</span> <span class="token punctuation">(</span>S_SUPPKEY<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tpch<span class="token punctuation">.</span>SUPPLIER<span class="token keyword">ADD</span> <span class="token keyword">FOREIGN</span> <span class="token keyword">KEY</span> SUPPLIER_FK1 <span class="token punctuation">(</span>S_NATIONKEY<span class="token punctuation">)</span> <span class="token keyword">references</span> tpch<span class="token punctuation">.</span>NATION<span class="token punctuation">(</span>N_NATIONKEY<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token keyword">COMMIT</span> <span class="token keyword">WORK</span><span class="token punctuation">;</span><span class="token comment">-- For table PARTSUPP</span><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tpch<span class="token punctuation">.</span>PARTSUPP<span class="token keyword">ADD</span> <span class="token keyword">PRIMARY</span> <span class="token keyword">KEY</span> <span class="token punctuation">(</span>PS_PARTKEY<span class="token punctuation">,</span>PS_SUPPKEY<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token keyword">COMMIT</span> <span class="token keyword">WORK</span><span class="token punctuation">;</span><span class="token comment">-- For table CUSTOMER</span><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tpch<span class="token punctuation">.</span>CUSTOMER<span class="token keyword">ADD</span> <span class="token keyword">PRIMARY</span> <span class="token keyword">KEY</span> <span class="token punctuation">(</span>C_CUSTKEY<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tpch<span class="token punctuation">.</span>CUSTOMER<span class="token keyword">ADD</span> <span class="token keyword">FOREIGN</span> <span class="token keyword">KEY</span> CUSTOMER_FK1 <span class="token punctuation">(</span>C_NATIONKEY<span class="token punctuation">)</span> <span class="token keyword">references</span> tpch<span class="token punctuation">.</span>NATION<span class="token punctuation">(</span>N_NATIONKEY<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token keyword">COMMIT</span> <span class="token keyword">WORK</span><span class="token punctuation">;</span><span class="token comment">-- For table LINEITEM</span><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tpch<span class="token punctuation">.</span>LINEITEM<span class="token keyword">ADD</span> <span class="token keyword">PRIMARY</span> <span class="token keyword">KEY</span> <span class="token punctuation">(</span>L_ORDERKEY<span class="token punctuation">,</span>L_LINENUMBER<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token keyword">COMMIT</span> <span class="token keyword">WORK</span><span class="token punctuation">;</span><span class="token comment">-- For table ORDERS</span><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tpch<span class="token punctuation">.</span>ORDERS<span class="token keyword">ADD</span> <span class="token keyword">PRIMARY</span> <span class="token keyword">KEY</span> <span class="token punctuation">(</span>O_ORDERKEY<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token keyword">COMMIT</span> <span class="token keyword">WORK</span><span class="token punctuation">;</span><span class="token comment">-- For table PARTSUPP</span><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tpch<span class="token punctuation">.</span>PARTSUPP<span class="token keyword">ADD</span> <span class="token keyword">FOREIGN</span> <span class="token keyword">KEY</span> PARTSUPP_FK1 <span class="token punctuation">(</span>PS_SUPPKEY<span class="token punctuation">)</span> <span class="token keyword">references</span> tpch<span class="token punctuation">.</span>SUPPLIER<span class="token punctuation">(</span>S_SUPPKEY<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token keyword">COMMIT</span> <span class="token keyword">WORK</span><span class="token punctuation">;</span><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tpch<span class="token punctuation">.</span>PARTSUPP<span class="token keyword">ADD</span> <span class="token keyword">FOREIGN</span> <span class="token keyword">KEY</span> PARTSUPP_FK2 <span class="token punctuation">(</span>PS_PARTKEY<span class="token punctuation">)</span> <span class="token keyword">references</span> tpch<span class="token punctuation">.</span>PART<span class="token punctuation">(</span>P_PARTKEY<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token keyword">COMMIT</span> <span class="token keyword">WORK</span><span class="token punctuation">;</span><span class="token comment">-- For table ORDERS</span><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tpch<span class="token punctuation">.</span>ORDERS<span class="token keyword">ADD</span> <span class="token keyword">FOREIGN</span> <span class="token keyword">KEY</span> ORDERS_FK1 <span class="token punctuation">(</span>O_CUSTKEY<span class="token punctuation">)</span> <span class="token keyword">references</span> tpch<span class="token punctuation">.</span>CUSTOMER<span class="token punctuation">(</span>C_CUSTKEY<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token keyword">COMMIT</span> <span class="token keyword">WORK</span><span class="token punctuation">;</span><span class="token comment">-- For table LINEITEM</span><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tpch<span class="token punctuation">.</span>LINEITEM<span class="token keyword">ADD</span> <span class="token keyword">FOREIGN</span> <span class="token keyword">KEY</span> LINEITEM_FK1 <span class="token punctuation">(</span>L_ORDERKEY<span class="token punctuation">)</span> <span class="token keyword">references</span> tpch<span class="token punctuation">.</span>ORDERS<span class="token punctuation">(</span>O_ORDERKEY<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token keyword">COMMIT</span> <span class="token keyword">WORK</span><span class="token punctuation">;</span><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tpch<span class="token punctuation">.</span>LINEITEM<span class="token keyword">ADD</span> <span class="token keyword">FOREIGN</span> <span class="token keyword">KEY</span> LINEITEM_FK2 <span class="token punctuation">(</span>L_PARTKEY<span class="token punctuation">,</span>L_SUPPKEY<span class="token punctuation">)</span> <span class="token keyword">references</span>tpch<span class="token punctuation">.</span>PARTSUPP<span class="token punctuation">(</span>PS_PARTKEY<span class="token punctuation">,</span>PS_SUPPKEY<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token keyword">alter</span> <span class="token keyword">table</span> CUSTOMER <span class="token keyword">rename</span> <span class="token keyword">to</span> customer <span class="token punctuation">;</span><span class="token keyword">alter</span> <span class="token keyword">table</span> LINEITEM <span class="token keyword">rename</span> <span class="token keyword">to</span> lineitem <span class="token punctuation">;</span><span class="token keyword">alter</span> <span class="token keyword">table</span> NATION <span class="token keyword">rename</span> <span class="token keyword">to</span> nation <span class="token punctuation">;</span><span class="token keyword">alter</span> <span class="token keyword">table</span> ORDERS <span class="token keyword">rename</span> <span class="token keyword">to</span> orders <span class="token punctuation">;</span><span class="token keyword">alter</span> <span class="token keyword">table</span> PART <span class="token keyword">rename</span> <span class="token keyword">to</span> part <span class="token punctuation">;</span><span class="token keyword">alter</span> <span class="token keyword">table</span> PARTSUPP <span class="token keyword">rename</span> <span class="token keyword">to</span> partsupp <span class="token punctuation">;</span><span class="token keyword">alter</span> <span class="token keyword">table</span> REGION <span class="token keyword">rename</span> <span class="token keyword">to</span> region <span class="token punctuation">;</span><span class="token keyword">alter</span> <span class="token keyword">table</span> SUPPLIER <span class="token keyword">rename</span> <span class="token keyword">to</span> supplier <span class="token punctuation">;</span><span class="token keyword">COMMIT</span> <span class="token keyword">WORK</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h4 id="建表"><a href="#建表" class="headerlink" title="建表"></a>建表</h4><h5 id="修改MySQL配置"><a href="#修改MySQL配置" class="headerlink" title="修改MySQL配置"></a>修改MySQL配置</h5><p>在建表之前我们需要先修改MySQL的一些配置。一些版本的mysql对通过文件导入导出作了限制，默认不允许。</p><p>查看配置，执行以下MySQL命令：</p><pre class="line-numbers language-sql" data-language="sql"><code class="language-sql"><span class="token keyword">SHOW</span> VARIABLES <span class="token operator">LIKE</span> <span class="token string">"secure_file_priv"</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>如果value值为null，则为禁止；如果有文件夹目录，则只允许改目录下文件（测试子目录也不行）；如果为空，则不限制目录。</p><p>修改MySQL配置文件 <code>my.cnf</code> ，查看是否有 <code>secure_file_priv=</code> 这一行的内容，如果没有则需要手动添加。我这里是直接置空：</p><pre class="line-numbers language-sql" data-language="sql"><code class="language-sql">secure_file_priv<span class="token operator">=</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>表示不限制目录。<strong>等号一定要有，否则mysql无法启动</strong>。修改完配置文件后，重启MySQL生效。</p><h5 id="生成数据表"><a href="#生成数据表" class="headerlink" title="生成数据表"></a>生成数据表</h5><p>开启MySQL服务，登录MySQL，使用命令 <code>\. path-to-tpc-h/dbgen/dss.ddl</code> 或者 <code>source path-to-tpc-h/dbgen/dss.ddl</code> 来使用修改后的 <code>dss.dll</code>文件创建数据表</p><p><img src="/2024/05/19/linux-huan-jing-xia-shi-yong-tpc-h-ce-shi-mysql-jiao-cheng/%E5%AF%BC%E5%85%A5%E5%91%BD%E4%BB%A4.png" alt="导入 dss.dll 的命令"></p><p>执行成功后查看数据库会发现有一个名叫<code>tpch</code>的数据库；切换到数据库下可以看到由8张表。</p><p><img src="/2024/05/19/linux-huan-jing-xia-shi-yong-tpc-h-ce-shi-mysql-jiao-cheng/%E5%AF%BC%E5%85%A5%E5%90%8E%E7%BB%93%E6%9E%9C%E5%B1%95%E7%A4%BA.png" alt="导入后结果展示"></p><h5 id="建立关联关系"><a href="#建立关联关系" class="headerlink" title="建立关联关系"></a>建立关联关系</h5><p>与上述同理，使用命令 <code>\. path-to-tpc-h/dbgen/dss.ri</code> 或者 <code>source path-to-tpc-h/dbgen/dss.ri</code> 来使用修改后的 <code>dss.dll</code>文件创建表约束</p><p>如果想查看关联关系是否建立成功，可以通过命令 <code>show create table customer\G;</code> 查看</p><h3 id="导入-tbl-数据文件"><a href="#导入-tbl-数据文件" class="headerlink" title="导入 tbl 数据文件"></a>导入 <code>tbl</code> 数据文件</h3><p>由于我要导入的数据很大，导入数据的时间会很长，我写了一个数据导入的脚本进行操作。</p><p>首先创建了一个 <code>loaddata.sql</code> 文件，该文件有所有导入数据所需的SQL命令。文件内容如下：</p><pre class="line-numbers language-sql" data-language="sql"><code class="language-sql"><span class="token keyword">load</span> <span class="token keyword">data</span> <span class="token keyword">infile</span> <span class="token string">"/home/czhang/mysql-tpc-h/dbgen/part.tbl"</span> <span class="token keyword">into</span> <span class="token keyword">table</span> part <span class="token keyword">fields</span> <span class="token keyword">terminated</span> <span class="token keyword">by</span> <span class="token string">"|"</span><span class="token punctuation">;</span><span class="token keyword">load</span> <span class="token keyword">data</span> <span class="token keyword">infile</span> <span class="token string">"/home/czhang/mysql-tpc-h/dbgen/region.tbl"</span> <span class="token keyword">into</span> <span class="token keyword">table</span> region <span class="token keyword">fields</span> <span class="token keyword">terminated</span> <span class="token keyword">by</span> <span class="token string">"|"</span> <span class="token keyword">lines</span> <span class="token keyword">terminated</span> <span class="token keyword">by</span> <span class="token string">"|\n"</span><span class="token punctuation">;</span><span class="token keyword">load</span> <span class="token keyword">data</span> <span class="token keyword">infile</span> <span class="token string">"/home/czhang/mysql-tpc-h/dbgen/nation.tbl"</span> <span class="token keyword">into</span> <span class="token keyword">table</span> nation <span class="token keyword">fields</span> <span class="token keyword">terminated</span> <span class="token keyword">by</span> <span class="token string">"|"</span><span class="token punctuation">;</span><span class="token keyword">load</span> <span class="token keyword">data</span> <span class="token keyword">infile</span> <span class="token string">"/home/czhang/mysql-tpc-h/dbgen/customer.tbl"</span> <span class="token keyword">into</span> <span class="token keyword">table</span> customer <span class="token keyword">fields</span> <span class="token keyword">terminated</span> <span class="token keyword">by</span> <span class="token string">"|"</span><span class="token punctuation">;</span><span class="token keyword">load</span> <span class="token keyword">data</span> <span class="token keyword">infile</span> <span class="token string">"/home/czhang/mysql-tpc-h/dbgen/supplier.tbl"</span> <span class="token keyword">into</span> <span class="token keyword">table</span> supplier <span class="token keyword">fields</span> <span class="token keyword">terminated</span> <span class="token keyword">by</span> <span class="token string">"|"</span> <span class="token keyword">lines</span> <span class="token keyword">terminated</span> <span class="token keyword">by</span> <span class="token string">"|\n"</span><span class="token punctuation">;</span><span class="token keyword">load</span> <span class="token keyword">data</span> <span class="token keyword">infile</span> <span class="token string">"/home/czhang/mysql-tpc-h/dbgen/orders.tbl"</span> <span class="token keyword">into</span> <span class="token keyword">table</span> orders <span class="token keyword">fields</span> <span class="token keyword">terminated</span> <span class="token keyword">by</span> <span class="token string">"|"</span><span class="token punctuation">;</span><span class="token keyword">load</span> <span class="token keyword">data</span> <span class="token keyword">infile</span> <span class="token string">"/home/czhang/mysql-tpc-h/dbgen/partsupp.tbl"</span> <span class="token keyword">into</span> <span class="token keyword">table</span> partsupp <span class="token keyword">fields</span> <span class="token keyword">terminated</span> <span class="token keyword">by</span> <span class="token string">"|"</span><span class="token punctuation">;</span><span class="token keyword">load</span> <span class="token keyword">data</span> <span class="token keyword">infile</span> <span class="token string">"/home/czhang/mysql-tpc-h/dbgen/lineitem.tbl"</span> <span class="token keyword">into</span> <span class="token keyword">table</span> lineitem <span class="token keyword">fields</span> <span class="token keyword">terminated</span> <span class="token keyword">by</span> <span class="token string">"|"</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>需要注意的是添加了关联关系，<strong>导入数据的顺序按照关联关系导入</strong></p><p>之后编写bash脚本进行导入，脚本内容如下：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token shebang important">#!/bin/bash</span>mysql -u root -pPASSWORD tpch <span class="token operator"><</span> /home/czhang/mysql-tpc-h/loaddata.sql<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><p>将 <code>PASSWORD</code>改成自己登录数据库的密码，数据库名和SQL命令文件路径改成自己的。</p><p>随后运行该脚本即可</p><p>导入完成后可运行以下SQL命令查看导入结果：</p><pre class="line-numbers language-sql" data-language="sql"><code class="language-sql"><span class="token keyword">SHOW</span> <span class="token keyword">TABLE</span> <span class="token keyword">STATUS</span> <span class="token keyword">FROM</span> tpch<span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><h3 id="生成查询语句"><a href="#生成查询语句" class="headerlink" title="生成查询语句"></a>生成查询语句</h3><p>前面介绍了 DBGEN ，是用来生成表与数据的，现在来介绍 QGEN ，这也是编译后生成的可执行文件，主要是用来生成查询 SQL 语句的，同样的，和dbgen一样，可以再README中查看该命令的介绍。</p><p>编写一个脚本用于生成查询语句，该脚本位于 <code>dbgen</code>文件夹下，脚本内容如下：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token shebang important">#! /bin/bash</span><span class="token comment"># 拷贝 dists.dss (SQL语句格式化参考) 与 qgen (生成SQL的可执行文件) 到官方提供的 queries (22条未格式化的SQL语句) 目录</span><span class="token function">cp</span> dists.dss qgen queries/<span class="token builtin class-name">cd</span> queries/<span class="token keyword">for</span> <span class="token for-or-select variable">i</span> <span class="token keyword">in</span> <span class="token punctuation">{</span><span class="token number">1</span><span class="token punctuation">..</span><span class="token number">22</span><span class="token punctuation">}</span><span class="token keyword">do</span> <span class="token function">sed</span> -i <span class="token string">"/^:n./d"</span> <span class="token variable">$i</span>.sql ./qgen -d <span class="token variable">$i</span> <span class="token operator">></span> d<span class="token variable">$i</span>.sql<span class="token keyword">done</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p><strong>注意</strong>：在生成查询语句前，queries文件夹中的 22 条未格式化的SQL语句 模板文件不要改动，否则<code>qgen</code>会读取错误导致无法生成正确的查询语句文件</p><p>运行脚本后，可以看到现在已经有了 22 个SQL脚本，分别存放的是 22 条测试语句，但是这些测试语句还不能直接使用，需要做些许修改。</p><p>修改一些变量的内容：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token comment"># 将所有 limit -1 替换为 limit 1</span><span class="token function">sed</span> -i <span class="token string">'$s/limit -1/limit 1/'</span> *.sql<span class="token comment"># 去掉脚本中的 date 函数</span><span class="token function">sed</span> -i <span class="token string">'s/ date / /g'</span> *.sql<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span></span></code></pre><p>然后需要手动修改一下 <code>1.sql</code> 、 <code>13.sql</code> 、<code>15.sql</code> 文件</p><pre class="line-numbers language-sql" data-language="sql"><code class="language-sql"><span class="token comment">################################# 1.sql ###########################</span><span class="token comment"># 将 where 条件的内容修改 </span><span class="token comment"># where</span><span class="token comment"># l_shipdate <= date '1998-12-01' - interval '90' day (3)</span><span class="token comment"># 修改为 如下</span><span class="token keyword">where</span>l_shipdate <span class="token operator"><=</span> <span class="token string">'1998-12-01'</span> <span class="token operator">-</span> <span class="token keyword">interval</span> <span class="token string">'90'</span> <span class="token keyword">day</span><span class="token comment">################################# 13.sql ##########################</span><span class="token comment"># 加上字段别名 </span><span class="token comment">#from</span><span class="token comment">#(</span><span class="token comment">#select</span><span class="token comment">#c_custkey,</span><span class="token comment">#count(o_orderkey)</span><span class="token keyword">from</span><span class="token punctuation">(</span><span class="token keyword">select</span>c_custkey<span class="token punctuation">,</span><span class="token function">count</span><span class="token punctuation">(</span>o_orderkey<span class="token punctuation">)</span> <span class="token keyword">as</span> c_count<span class="token comment"># 去除掉 表别名</span><span class="token comment">#c_custkey</span><span class="token comment">#) as c_orders (c_custkey, c_count)</span><span class="token comment">#group by</span><span class="token comment">#c_count</span>c_custkey<span class="token punctuation">)</span> <span class="token keyword">as</span> c_orders<span class="token keyword">group</span> <span class="token keyword">by</span>c_count<span class="token comment">################################ 15.sql ############################</span><span class="token comment"># 以下是修改后的文件</span><span class="token keyword">use</span> tpch<span class="token punctuation">;</span> <span class="token keyword">with</span> revenue0 <span class="token punctuation">(</span>supplier_no<span class="token punctuation">,</span> total_revenue<span class="token punctuation">)</span> <span class="token keyword">as</span><span class="token punctuation">(</span><span class="token keyword">select</span>l_suppkey<span class="token punctuation">,</span><span class="token function">sum</span><span class="token punctuation">(</span>l_extendedprice <span class="token operator">*</span> <span class="token punctuation">(</span><span class="token number">1</span> <span class="token operator">-</span> l_discount<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token keyword">from</span>lineitem<span class="token keyword">where</span>l_shipdate <span class="token operator">>=</span> <span class="token string">'1996-01-01'</span><span class="token operator">and</span> l_shipdate <span class="token operator"><</span> <span class="token string">'1996-01-01'</span> <span class="token operator">+</span> <span class="token keyword">interval</span> <span class="token string">'3'</span> <span class="token keyword">month</span><span class="token keyword">group</span> <span class="token keyword">by</span>l_suppkey<span class="token punctuation">)</span><span class="token keyword">select</span>s_suppkey<span class="token punctuation">,</span>s_name<span class="token punctuation">,</span>s_address<span class="token punctuation">,</span>s_phone<span class="token punctuation">,</span>total_revenue<span class="token keyword">from</span>supplier<span class="token punctuation">,</span>revenue0<span class="token keyword">where</span>s_suppkey <span class="token operator">=</span> supplier_no<span class="token operator">and</span> total_revenue <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token keyword">select</span><span class="token function">max</span><span class="token punctuation">(</span>total_revenue<span class="token punctuation">)</span><span class="token keyword">from</span>revenue0<span class="token punctuation">)</span><span class="token keyword">order</span> <span class="token keyword">by</span>s_suppkey<span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>至此，整个SQL就修改完成了</p><h2 id="进行TPC-H基准测试"><a href="#进行TPC-H基准测试" class="headerlink" title="进行TPC-H基准测试"></a>进行TPC-H基准测试</h2><p>首先使用命令进行统一的修改。为每条 SQL 语句指名使用的数据库。</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token comment"># 在个 SQL 文件的第一行 添加 use tpch; 的语句。</span><span class="token function">sed</span> -i <span class="token string">'1a use tpch; \n'</span> *.sql<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><p>之后在 <code>queries</code>文件夹中运行命令：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token keyword">for</span> <span class="token for-or-select variable">i</span> <span class="token keyword">in</span> <span class="token punctuation">{</span><span class="token number">1</span><span class="token punctuation">..</span><span class="token number">22</span><span class="token punctuation">}</span><span class="token punctuation">;</span> <span class="token keyword">do</span> mysql -u root -p123456 <span class="token operator"><</span> d<span class="token variable">$i</span>.sql<span class="token punctuation">;</span> <span class="token keyword">done</span> <span class="token operator">></span> run.log <span class="token operator"><span class="token file-descriptor important">2</span>></span><span class="token file-descriptor important">&1</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>即可开始基准测试。</p><p><strong>Reference：</strong></p><p><a href="https://gitee.com/hel10word/tpc-h#dssddl">TPC-H在MemSQL的测试</a></p><p><a href="https://blog.csdn.net/weixin_38806650/article/details/122876798">linux环境下测试mysql+TPC-H（实测全流程：环境安装+导入数据+执行查询）</a></p><p><a href="https://blog.csdn.net/qq_41822345/article/details/117463499">MySQL性能测试——tpch工具</a></p>]]></content>
<categories>
<category> 工作负载 </category>
</categories>
<tags>
<tag> MySQL </tag>
<tag> 工作负载 </tag>
<tag> 环境搭建 </tag>
<tag> TPC-H </tag>
<tag> 安装教程 </tag>
</tags>
</entry>
<entry>
<title>二叉树遍历代码模板</title>
<link href="/2024/05/08/er-cha-shu-bian-li-dai-ma-mo-ban/"/>
<url>/2024/05/08/er-cha-shu-bian-li-dai-ma-mo-ban/</url>
<content type="html"><![CDATA[<h2 id="1、二叉树的定义"><a href="#1、二叉树的定义" class="headerlink" title="1、二叉树的定义"></a>1、二叉树的定义</h2><pre class="line-numbers language-c++" data-language="c++"><code class="language-c++">strcut TreeNode{ int val; TreeNode* left; TreeNode* right; TreeNode(int x) : val(x),left(NULL),right(NULL){};}<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="2、二叉树的遍历"><a href="#2、二叉树的遍历" class="headerlink" title="2、二叉树的遍历"></a>2、二叉树的遍历</h2><ul><li>深度优先遍历<ul><li>前序遍历（递归法，迭代法）</li><li>中序遍历（递归法，迭代法）</li><li>后序遍历（递归法，迭代法）</li></ul></li><li>广度优先遍历<ul><li>层次遍历（迭代法）</li></ul></li></ul><h3 id="前-x2F-中-x2F-后序遍历："><a href="#前-x2F-中-x2F-后序遍历：" class="headerlink" title="前/中/后序遍历："></a><strong>前/中/后序遍历：</strong></h3><pre class="line-numbers language-c++" data-language="c++"><code class="language-c++">class Solution{public: // 前序遍历 void traversal(TreeNode* cur,vector<int>& res){ // 要加& if(cur == NULL){ return; } res.push_back(cur->val); // 根 traversal(cur->left,res); // 左 traversal(cur->right,res); // 右 } // 中序遍历 void traversal(TreeNode* cur, vector<int>& vec) { if (cur == NULL){ return; } traversal(cur->left, vec); // 左 vec.push_back(cur->val); // 根 traversal(cur->right, vec); // 右 } // 后序遍历 void traversal(TreeNode* cur, vector<int>& vec) { if (cur == NULL){ return; } traversal(cur->left, vec); // 左 traversal(cur->right, vec); // 右 vec.push_back(cur->val); // 根 } vector<int> PreorderTraversal(TreeNode* root){ vector<int> res; traversal(root,res); return res; }}<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h3 id="层序遍历："><a href="#层序遍历：" class="headerlink" title="层序遍历："></a><strong>层序遍历：</strong></h3><pre class="line-numbers language-c++" data-language="c++"><code class="language-c++">class Solution {public: vector<vector<int>> levelOrder(TreeNode* root) { queue<TreeNode*> q; vector<vector<int>> res; if(root != nullptr){ q.push(root); } while(!q.empty()){ vector<int> temp; int size = q.size(); // 存放这一层节点个数 for(int i = 0;i < size;i++){ TreeNode* p = q.front(); q.pop(); temp.push_back(p->val); if(p->left != nullptr){ q.push(p->left); } if(p->right != nullptr){ q.push(p->right); } } res.push_back(temp); } return res; }};// 输入：root = [3,9,20,null,null,15,7] 输出：[[3],[9,20],[15,7]]<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><ul><li>二叉树节点的<strong>深度</strong>：指从<strong>根节点</strong>到<strong>该节点</strong>的最长简单路径边的条数。</li><li>二叉树节点的<strong>高度</strong>：指从<strong>该节点</strong>到<strong>叶子节点</strong>的最长简单路径边的条数。</li></ul><p>求<strong>深度</strong>可以从上到下去查，所以需要<strong>前序遍历</strong>（根左右），而<strong>高度</strong>需要从下到上去查，所以要<strong>后序遍历</strong>（左右根）</p><h2 id="3、二叉搜索树（二叉排序树）"><a href="#3、二叉搜索树（二叉排序树）" class="headerlink" title="3、二叉搜索树（二叉排序树）"></a>3、二叉搜索树（二叉排序树）</h2><p>遇到在<strong>二叉搜索树（二叉排序树）</strong>上求什么<strong>最值</strong>，求<strong>差值</strong>之类的，都要思考一下二叉搜索树可是<strong>有序的</strong>，要利用好这一特点</p><p>如果递归函数有返回值，如何区分要搜索一条边，还是搜索整个树：</p><p><strong>搜索一条边的写法：</strong></p><pre class="line-numbers language-c++" data-language="c++"><code class="language-c++">if (递归函数(root->left)) return ;if (递归函数(root->right)) return ;<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><p><strong>搜索整个树写法：</strong></p><pre class="line-numbers language-c++" data-language="c++"><code class="language-c++">left = 递归函数(root->left);right = 递归函数(root->right);left与right的逻辑处理;<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span></span></code></pre><p><strong>选择什么遍历顺序:</strong></p><ul><li>涉及到二叉树的构造，无论普通二叉树还是二叉搜索树一定前序，都是先构造中节点。</li><li>求普通二叉树的属性，一般是后序，一般要通过递归函数的返回值做计算。(具体问题具体分析)也有用前序的</li><li>求二叉搜索树的属性，一定是中序了，要不白瞎了有序性了。</li></ul><p><img src="/2024/05/08/er-cha-shu-bian-li-dai-ma-mo-ban/%E4%BA%8C%E5%8F%89%E6%A0%91%E7%9B%B8%E5%85%B3%E7%9F%A5%E8%AF%86%E5%BD%92%E7%BA%B3.png" alt="二叉树相关知识归纳"></p>]]></content>
<categories>
<category> 算法 </category>
</categories>
<tags>
<tag> 树 </tag>
<tag> 二叉树 </tag>
<tag> 二叉树的遍历 </tag>
</tags>
</entry>
<entry>
<title>C++刷题STL</title>
<link href="/2024/05/07/c-shua-ti-stl/"/>
<url>/2024/05/07/c-shua-ti-stl/</url>
<content type="html"><![CDATA[<h1 id="C-之刷题常用STL容器整理"><a href="#C-之刷题常用STL容器整理" class="headerlink" title="C++之刷题常用STL容器整理"></a>C++之刷题常用STL容器整理</h1><h2 id="1-vector"><a href="#1-vector" class="headerlink" title="1.vector"></a>1.vector</h2><p>动态数组，方便的动态扩容，方便的变量初始化（int类型默认初始化为0，bool默认初始化为false），可以用来实现邻接表（结点数太多的图）。</p><p>头文件</p><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp"><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><vector></span></span><span class="token keyword">using</span> <span class="token keyword">namespace</span> std<span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><p>定义</p><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp"><span class="token comment">//typename 可以是基本数据类型，可以是其它标准stl容器，可以是自定义结构体</span>vector<span class="token operator"><</span><span class="token keyword">typename</span><span class="token operator">></span> name<span class="token punctuation">;</span>vector<span class="token operator"><</span><span class="token keyword">int</span><span class="token operator">></span> v1<span class="token punctuation">;</span>vector<span class="token operator"><</span>vector<span class="token operator"><</span><span class="token keyword">int</span><span class="token operator">></span> <span class="token operator">></span> v2<span class="token punctuation">;</span> <span class="token comment">//两个维度都是动态的</span>vector<span class="token operator"><</span>student<span class="token operator">></span> <span class="token function">v3</span><span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//一维固定为10，二维动态</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>元素访问</p><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp"><span class="token comment">//1.下标访问</span>v<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token comment">//2.迭代器访问</span>vector<span class="token operator"><</span><span class="token keyword">typename</span><span class="token operator">></span><span class="token double-colon punctuation">::</span>iterator it<span class="token punctuation">;</span><span class="token keyword">auto</span> it<span class="token punctuation">;</span><span class="token comment">//另一种迭代器简易定义方法</span><span class="token keyword">for</span><span class="token punctuation">(</span><span class="token keyword">auto</span> it <span class="token operator">=</span> v<span class="token punctuation">.</span><span class="token function">begin</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>it<span class="token operator">!=</span>v<span class="token punctuation">.</span><span class="token function">end</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>it<span class="token operator">++</span><span class="token punctuation">)</span> cout<span class="token operator"><<</span><span class="token operator">*</span>it<span class="token punctuation">;</span><span class="token comment">//迭代器it可以进行算术运算</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>常用函数</p><table><thead><tr><th>函数</th><th>说明</th></tr></thead><tbody><tr><td>push_back(x);</td><td>将元素x添加到容器末尾</td></tr><tr><td>pop_back();</td><td>删除容器末尾元素</td></tr><tr><td>size();</td><td>获取容器大小</td></tr><tr><td>clear();</td><td>清空元素</td></tr><tr><td>insert(it,x);</td><td>在it处插入一个元素x</td></tr><tr><td>erase(it);</td><td>删除it处的元素</td></tr><tr><td>erase(first,last);</td><td>删除[first,last)区间内的元素</td></tr></tbody></table><p>使用场景</p><ul><li>元素个数不确定</li><li>用于实现邻接表存储图</li></ul><h2 id="2-set"><a href="#2-set" class="headerlink" title="2.set"></a>2.set</h2><p>内部自动有序且不含重复元素的集合。</p><p>头文件</p><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp"><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><set></span></span><span class="token keyword">using</span> <span class="token keyword">namespace</span> std<span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><p>定义</p><pre class="line-numbers language-c" data-language="c"><code class="language-c">set<span class="token operator"><</span>typename<span class="token operator">></span> name<span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>元素访问</p><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp"><span class="token keyword">for</span><span class="token punctuation">(</span><span class="token keyword">auto</span> it <span class="token operator">=</span> v<span class="token punctuation">.</span><span class="token function">begin</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>it<span class="token operator">!=</span>v<span class="token punctuation">.</span><span class="token function">end</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>it<span class="token operator">++</span><span class="token punctuation">)</span> cout<span class="token operator"><<</span><span class="token operator">*</span>it<span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><p>常用函数</p><table><thead><tr><th>函数</th><th>说明</th></tr></thead><tbody><tr><td>insert(x);</td><td>将元素x插入set容器中，并自动递增排序和去重</td></tr><tr><td>find(value);</td><td>查找值为value的元素，返回对应迭代器</td></tr><tr><td>erase(it);</td><td>删除it处的元素，通常结合find函数使用</td></tr><tr><td>erase(value);</td><td>删除值为value的元素</td></tr><tr><td>erase(first,last);</td><td>删除[first,last)区间内的元素</td></tr><tr><td>size();</td><td>返回容器大小</td></tr><tr><td>clear();</td><td>清空容器</td></tr></tbody></table><p>使用场景：</p><ul><li>自动去重并按升序排序</li></ul><p>扩展：</p><ul><li>需要元素不唯一，使用multiset</li><li>需要元素不排序，unordered_set（內部以散列代替了set内部的红黑树），速度比set快得多</li></ul><h2 id="3-string"><a href="#3-string" class="headerlink" title="3.string"></a>3.string</h2><p>字符串，可以替换为C语言版的字符数组（str.c_str();）。</p><p>头文件</p><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp"><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><string></span></span><span class="token keyword">using</span> <span class="token keyword">namespace</span> std<span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><p>定义</p><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp">string str<span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>内容访问</p><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp"><span class="token comment">//1.下标访问</span>str<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token comment">//2.输入输出只能用cin和cout，除非转化为字符数组</span><span class="token comment">//3.迭代器访问</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>常用函数</p><table><thead><tr><th>函数</th><th>说明</th></tr></thead><tbody><tr><td>operator+=</td><td>字符串拼接</td></tr><tr><td>compare operator</td><td>按照字典序比较大小</td></tr><tr><td>length()/size()</td><td>获取字符串大小</td></tr><tr><td>insert(pos,str);</td><td>pos是int类型，表示在指定位置插入str</td></tr><tr><td>insert(it,first,last);</td><td>在it处插入[first,last)范围内的字符串</td></tr><tr><td>erase(it);</td><td>删除it处的元素</td></tr><tr><td>erase(first,last);</td><td>删除[first,last)范围内的元素</td></tr><tr><td>erase(pos,length);</td><td>删除pos位置开始的length个字符</td></tr><tr><td>clear();</td><td>清空字符串</td></tr><tr><td>substr(pos,len);</td><td>返回从pos位置开始len长度的字符串</td></tr><tr><td>string::npos</td><td>作为find函数未找到的判断依据</td></tr><tr><td>find(str);</td><td>返回str第一次出现的位置</td></tr><tr><td>replace(pos,len,str2);</td><td>从pos位置开始，长度为len的子串替换为str2</td></tr></tbody></table><h2 id="4-map"><a href="#4-map" class="headerlink" title="4.map"></a>4.map</h2><p>将任何基本类型映射到任何基本类型（包括STL容器）。</p><p>可以用于hash散列（当元素个数比较多时，不适合用数组散列，就用map）</p><p>头文件及定义</p><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp"><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><map></span></span><span class="token keyword">using</span> <span class="token keyword">namespace</span> std<span class="token punctuation">;</span>map<span class="token operator"><</span>typename1<span class="token punctuation">,</span>typename2<span class="token operator">></span> mp<span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span></span></code></pre><p>元素访问</p><pre class="line-numbers language-c" data-language="c"><code class="language-c"><span class="token comment">//1.下标</span>mp<span class="token punctuation">[</span><span class="token char">'c'</span><span class="token punctuation">]</span>mp<span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span>mp<span class="token punctuation">[</span><span class="token string">"key"</span><span class="token punctuation">]</span><span class="token comment">//2.迭代器</span><span class="token keyword">for</span><span class="token punctuation">(</span><span class="token keyword">auto</span> it <span class="token operator">=</span> mp<span class="token punctuation">.</span><span class="token function">begin</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> it <span class="token operator">!=</span> mp<span class="token punctuation">.</span><span class="token function">end</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> it<span class="token operator">++</span><span class="token punctuation">)</span><span class="token punctuation">{</span>cout<span class="token operator"><<</span> it<span class="token operator">-></span>first<span class="token operator"><<</span><span class="token string">" "</span><span class="token operator"><<</span>it<span class="token operator">-></span>second<span class="token punctuation">;</span><span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>常用函数</p><table><thead><tr><th>函数</th><th>说明</th></tr></thead><tbody><tr><td>find(key);</td><td>返回键为key的映射的迭代器</td></tr><tr><td>erase(it);</td><td>删除it处的元素</td></tr><tr><td>erase(key);</td><td>删除key</td></tr><tr><td>erase(first,last);</td><td>删除[first,last)区间内的元素</td></tr><tr><td>size();</td><td>返回容器大小</td></tr><tr><td>clear();</td><td>清空容器</td></tr></tbody></table><p>使用场景：</p><ul><li>散列表</li><li>其他映射</li></ul><p>扩展：</p><ul><li>多映射，即一个key对应多个value，使用multimap</li><li>unordered_map可以替代map，内部实现使用散列代替了map内部的红黑树实现，用于处理只映射而不需要按key来排序的需求，速度快</li></ul><h2 id="5-queue"><a href="#5-queue" class="headerlink" title="5.queue"></a>5.queue</h2><p>队列，先进先出的容器，常用于广度优先搜索</p><p>头文件及定义</p><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp"><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><queue></span></span><span class="token keyword">using</span> <span class="token keyword">namespace</span> std<span class="token punctuation">;</span>queue<span class="token operator"><</span><span class="token keyword">typename</span><span class="token operator">></span> name<span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span></span></code></pre><p>常用函数</p><table><thead><tr><th>函数</th><th>说明</th></tr></thead><tbody><tr><td>push(x);</td><td>元素x入队列</td></tr><tr><td>front();</td><td>访问队列的首元素</td></tr><tr><td>back();</td><td>访问队列的尾元素</td></tr><tr><td>pop();</td><td>队首元素出队</td></tr><tr><td>empty();</td><td>检测是否为空队列</td></tr><tr><td>size();</td><td>队列大小</td></tr></tbody></table><p>使用场景</p><ul><li>广度优先搜索</li></ul><p><strong>另外</strong>，需要注意使用front()，back(), pop()函数前，必须判断是否为空队列（使用empty函数）</p><p>扩展</p><ul><li>deque(double end queue,双端队列)首位皆可插入和删除</li><li>priority_queue，使用堆实现的默认将当前队列最大元素置于队首的容器</li></ul><h2 id="6-priority-queue"><a href="#6-priority-queue" class="headerlink" title="6.priority_queue"></a>6.priority_queue</h2><p>优先队列，默认情况下是将队列中最大元素置于队首，优先级可以自定义。每次进行push(),pop()操作，底层的数据结构堆（heap）都会随时调整结构，使优先级最高的元素永远都在队首。</p><p>头文件及定义</p><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp"><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><queue></span></span><span class="token keyword">using</span> <span class="token keyword">namespace</span> std<span class="token punctuation">;</span>priority_queue<span class="token operator"><</span><span class="token keyword">typename</span><span class="token operator">></span> name<span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span></span></code></pre><p>常用函数</p><table><thead><tr><th>函数</th><th>说明</th></tr></thead><tbody><tr><td>push(x);</td><td>将元素x入队</td></tr><tr><td>top();</td><td>访问队首元素</td></tr><tr><td>pop();</td><td>将队首元素出队</td></tr><tr><td>empty();</td><td>检测是否为空队列</td></tr><tr><td>size();</td><td>返回队列大小</td></tr></tbody></table><p>优先级设定</p><p>基本数据类型（int,double,char）默认数字大或者字典序大的优先级高。</p><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp">priority_queue<span class="token operator"><</span><span class="token keyword">int</span><span class="token punctuation">,</span>vector<span class="token operator"><</span><span class="token keyword">int</span><span class="token operator">></span><span class="token punctuation">,</span>greater<span class="token operator"><</span><span class="token keyword">int</span><span class="token operator">>></span> q<span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><ul><li>greater表示这个数字越小，优先级越高</li><li>less表示数字越大，优先级越高（默认情况）</li></ul><p>vector表示底层数据结构堆（heap）的容器</p><p>结构体优先级设置</p><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp"><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><iostream></span></span><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><string></span></span><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><queue></span></span><span class="token keyword">using</span> <span class="token keyword">namespace</span> std<span class="token punctuation">;</span><span class="token keyword">struct</span> <span class="token class-name">fruit</span><span class="token punctuation">{</span> string name<span class="token punctuation">;</span> <span class="token keyword">int</span> price<span class="token punctuation">;</span> <span class="token keyword">friend</span> <span class="token keyword">bool</span> <span class="token keyword">operator</span> <span class="token operator"><</span> <span class="token punctuation">(</span>fruit f1<span class="token punctuation">,</span>fruit f2<span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">return</span> f1<span class="token punctuation">.</span>price <span class="token operator">></span> f2<span class="token punctuation">.</span>price<span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token punctuation">}</span>f1<span class="token punctuation">,</span>f2<span class="token punctuation">,</span>f3<span class="token punctuation">;</span><span class="token keyword">int</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span> priority_queue<span class="token operator"><</span>fruit<span class="token operator">></span> q<span class="token punctuation">;</span> f1<span class="token punctuation">.</span>name <span class="token operator">=</span> <span class="token string">"桃子"</span><span class="token punctuation">;</span> f1<span class="token punctuation">.</span>price <span class="token operator">=</span> <span class="token number">3</span><span class="token punctuation">;</span> f2<span class="token punctuation">.</span>name <span class="token operator">=</span> <span class="token string">"梨子"</span><span class="token punctuation">;</span> f2<span class="token punctuation">.</span>price <span class="token operator">=</span> <span class="token number">4</span><span class="token punctuation">;</span> f3<span class="token punctuation">.</span>name <span class="token operator">=</span> <span class="token string">"苹果"</span><span class="token punctuation">;</span> f3<span class="token punctuation">.</span>price <span class="token operator">=</span> <span class="token number">1</span><span class="token punctuation">;</span> q<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span>f1<span class="token punctuation">)</span><span class="token punctuation">;</span> q<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span>f2<span class="token punctuation">)</span><span class="token punctuation">;</span> q<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span>f3<span class="token punctuation">)</span><span class="token punctuation">;</span> cout<span class="token operator"><<</span> q<span class="token punctuation">.</span><span class="token function">top</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span>name<span class="token operator"><<</span><span class="token string">" "</span><span class="token operator"><<</span>q<span class="token punctuation">.</span><span class="token function">top</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span>price <span class="token operator"><<</span>endl<span class="token punctuation">;</span> <span class="token keyword">return</span> <span class="token number">0</span><span class="token punctuation">;</span><span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>output:</p><pre class="line-numbers language-none"><code class="language-none">苹果 1<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>使用场景</p><p>可以用于dijkstra算法的顶点选择中</p><p>注意使用top()函数之前判断队列是否为空（使用empty()函数）</p><h2 id="7-stack"><a href="#7-stack" class="headerlink" title="7.stack"></a>7.stack</h2><p>栈，先进后出</p><p>头文件及定义</p><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp"><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><stack></span></span><span class="token keyword">using</span> <span class="token keyword">namespace</span> std<span class="token punctuation">;</span>stack<span class="token operator"><</span><span class="token keyword">typename</span><span class="token operator">></span> name<span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span></span></code></pre><p>常用函数</p><table><thead><tr><th>函数</th><th>说明</th></tr></thead><tbody><tr><td>push(x);</td><td>元素x入栈</td></tr><tr><td>top();</td><td>获取栈顶元素</td></tr><tr><td>pop();</td><td>栈顶元素出栈</td></tr><tr><td>empty();</td><td>检测stack是否为空</td></tr><tr><td>size()；</td><td>获取栈的大小</td></tr></tbody></table><p>使用场景</p><p>递归模拟，防止递归深度过深，深度优先搜索模拟。</p><h2 id="8-pair"><a href="#8-pair" class="headerlink" title="8.pair"></a>8.pair</h2><p>头文件及使用</p><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp"><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><utility></span></span><span class="token keyword">using</span> <span class="token keyword">namespace</span> std<span class="token punctuation">;</span><span class="token comment">//map实现中涉及pair，使用map时自动添加了该头文件</span>pair<span class="token operator"><</span>typename1<span class="token punctuation">,</span>typename2<span class="token operator">></span> name<span class="token punctuation">;</span>pair<span class="token operator"><</span>string <span class="token punctuation">,</span><span class="token keyword">int</span> <span class="token operator">></span> <span class="token function">p</span><span class="token punctuation">(</span><span class="token string">"hahahah"</span><span class="token punctuation">,</span><span class="token number">7</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token function">make_pair</span><span class="token punctuation">(</span><span class="token string">"haha"</span><span class="token punctuation">,</span><span class="token number">4</span><span class="token punctuation">)</span><span class="token punctuation">;</span>cout<span class="token operator"><<</span>p<span class="token punctuation">.</span>first<span class="token operator"><<</span><span class="token string">" "</span><span class="token operator"><<</span>p<span class="token punctuation">.</span>second<span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre>]]></content>
<categories>
<category> 小知识 </category>
</categories>
<tags>
<tag> C++ </tag>
<tag> 算法 </tag>
<tag> 小知识 </tag>
</tags>
</entry>
<entry>
<title>C++刷题API</title>
<link href="/2024/05/07/c-shua-ti-api/"/>
<url>/2024/05/07/c-shua-ti-api/</url>
<content type="html"><![CDATA[<h2 id="1-数组"><a href="#1-数组" class="headerlink" title="1.数组"></a>1.数组</h2><pre class="line-numbers language-c++" data-language="c++"><code class="language-c++">#include<iostream>#include<algorithm>using namespace std;int main() { int arr[] = {5, 4, 1, 7, 2}; //定义时创建数组 int length = sizeof(arr) / sizeof(int); // 求出数组的长度 cout << length << endl; sort(arr, arr + 5); for (int e : arr) cout << e << " "; int* arr2 = new int[10]; delete [] arr2;}<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="2-char"><a href="#2-char" class="headerlink" title="2.char"></a>2.char</h2><pre class="line-numbers language-java" data-language="java"><code class="language-java">#include<span class="token generics"><span class="token punctuation"><</span>iostream<span class="token punctuation">></span></span>#include<span class="token generics"><span class="token punctuation"><</span>cstring<span class="token punctuation">></span></span>using namespace std<span class="token punctuation">;</span><span class="token keyword">int</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">char</span> c <span class="token operator">=</span> <span class="token char">'A'</span><span class="token punctuation">;</span> bool is <span class="token operator">=</span> <span class="token function">isalpha</span><span class="token punctuation">(</span>c<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//字母(包括大小写)</span> cout <span class="token operator"><<</span> is <span class="token operator"><<</span> endl<span class="token punctuation">;</span> <span class="token comment">//true:1</span> bool is2 <span class="token operator">=</span> <span class="token function">islower</span><span class="token punctuation">(</span>c<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//小写字母</span> bool is3 <span class="token operator">=</span> <span class="token function">isupper</span><span class="token punctuation">(</span>c<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//大写字母</span> bool is4 <span class="token operator">=</span> <span class="token function">isalnum</span><span class="token punctuation">(</span>c<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//字母大写小写 + 数字</span> bool is5 <span class="token operator">=</span> <span class="token function">isblank</span><span class="token punctuation">(</span>c<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//空格和 \t</span> bool is6 <span class="token operator">=</span> <span class="token function">isspace</span><span class="token punctuation">(</span>c<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//空格、\t、\r、\n</span> <span class="token keyword">char</span> cc <span class="token operator">=</span> <span class="token function">toupper</span><span class="token punctuation">(</span>c<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">char</span> tt <span class="token operator">=</span> <span class="token function">tolower</span><span class="token punctuation">(</span>c<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="3-string"><a href="#3-string" class="headerlink" title="3.string"></a>3.string</h2><pre class="line-numbers language-c++" data-language="c++"><code class="language-c++">#include<iostream>#include<cstring>#include<string>using namespace std;int main() { string s = "Hello,World";//赋值字符串 string s2 = s; //产生一个新的字符串 string s3 = s + s2; //字符串拼接 string s4; cin>>s4; //输入字符串 cout<<s4; //输出字符串 s.length(); //字符串的真实长度 getline(cin, s); //读取一行字符串，包括空格 string s7 = s.substr(4); // 表示从下标4开始一直到结束 string s8 = s.substr(5,3); //表示从下标5开始，3个字符}<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="4-vector"><a href="#4-vector" class="headerlink" title="4.vector"></a>4.vector</h2><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp"><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><iostream></span></span><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><vector></span></span><span class="token keyword">using</span> <span class="token keyword">namespace</span> std<span class="token punctuation">;</span><span class="token keyword">int</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token comment">//定义时不指定大小，不指定默认值</span> vector<span class="token operator"><</span><span class="token keyword">int</span><span class="token operator">></span> v<span class="token punctuation">;</span> <span class="token comment">//定义一个vector v，定义的时候没有分配大小</span> cout<span class="token operator"><<</span>v<span class="token punctuation">.</span><span class="token function">size</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//0</span> v<span class="token punctuation">.</span><span class="token function">resize</span><span class="token punctuation">(</span><span class="token number">8</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//动态分配大小为8，默认这8个元素都是0</span> <span class="token comment">//定义时指定大小，指定默认值</span> vector<span class="token operator"><</span><span class="token keyword">int</span><span class="token operator">></span> <span class="token function">c</span><span class="token punctuation">(</span><span class="token number">100</span><span class="token punctuation">,</span> <span class="token number">9</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//长度100，所有元素值为9</span> <span class="token comment">//增删改查</span> v<span class="token punctuation">.</span><span class="token function">push_back</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//末尾添加一个元素</span> <span class="token comment">//遍历</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">auto</span> it <span class="token operator">=</span> c<span class="token punctuation">.</span><span class="token function">begin</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> it <span class="token operator">!=</span> c<span class="token punctuation">.</span><span class="token function">end</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> it<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> cout<span class="token operator"><<</span> <span class="token operator">*</span>it <span class="token operator"><<</span> <span class="token string">" "</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="5-set-x2F-unordered-set"><a href="#5-set-x2F-unordered-set" class="headerlink" title="5.set/unordered_set"></a>5.set/unordered_set</h2><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp"><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><iostream></span></span><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><set></span></span><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><unordered_set></span></span><span class="token keyword">using</span> <span class="token keyword">namespace</span> std<span class="token punctuation">;</span><span class="token keyword">int</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> set<span class="token operator"><</span><span class="token keyword">int</span><span class="token operator">></span> s<span class="token punctuation">;</span> <span class="token comment">// 定义一个空集合s 有序的，二叉树实现，O(logN)</span> unordered_set<span class="token operator"><</span><span class="token keyword">int</span><span class="token operator">></span> set2<span class="token punctuation">;</span><span class="token comment">//无序的，哈希表实现，O(1)</span> s<span class="token punctuation">.</span><span class="token function">insert</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//向集合s里面插入一个1</span> cout <span class="token operator"><<</span> <span class="token operator">*</span><span class="token punctuation">(</span>s<span class="token punctuation">.</span><span class="token function">begin</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token operator"><<</span> endl<span class="token punctuation">;</span> <span class="token comment">//输出集合s的第一个元素</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> <span class="token number">6</span><span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> s<span class="token punctuation">.</span><span class="token function">insert</span><span class="token punctuation">(</span>i <span class="token operator">*</span> <span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//插入</span> <span class="token punctuation">}</span> <span class="token comment">//遍历</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">auto</span> it <span class="token operator">=</span> s<span class="token punctuation">.</span><span class="token function">begin</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> it <span class="token operator">!=</span> s<span class="token punctuation">.</span><span class="token function">end</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> it<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> cout <span class="token operator"><<</span> <span class="token operator">*</span>it <span class="token operator"><<</span> <span class="token string">" "</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token comment">//查找一个元素</span> <span class="token comment">//找到为true:1.找不到为false:0</span> cout <span class="token operator"><<</span> <span class="token punctuation">(</span>s<span class="token punctuation">.</span><span class="token function">find</span><span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">)</span> <span class="token operator">!=</span> s<span class="token punctuation">.</span><span class="token function">end</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token operator"><<</span> endl<span class="token punctuation">;</span> <span class="token comment">//删除</span> s<span class="token punctuation">.</span><span class="token function">erase</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//删除集合s中的1这个元素</span> cout <span class="token operator"><<</span> <span class="token punctuation">(</span>s<span class="token punctuation">.</span><span class="token function">find</span><span class="token punctuation">(</span><span class="token number">3</span><span class="token punctuation">)</span> <span class="token operator">!=</span> s<span class="token punctuation">.</span><span class="token function">end</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token operator"><<</span> endl<span class="token punctuation">;</span><span class="token comment">//此时1已经找不到了</span> cout <span class="token operator"><<</span> <span class="token string">"true"</span> <span class="token operator"><<</span><span class="token punctuation">(</span><span class="token number">1</span> <span class="token operator">==</span> <span class="token number">1</span><span class="token punctuation">)</span> <span class="token operator"><<</span> endl<span class="token punctuation">;</span> <span class="token comment">//向下取整</span> cout <span class="token operator"><<</span> <span class="token operator">*</span>s<span class="token punctuation">.</span><span class="token function">lower_bound</span><span class="token punctuation">(</span><span class="token number">4</span><span class="token punctuation">)</span> <span class="token operator"><<</span> endl<span class="token punctuation">;</span><span class="token comment">//小于等于4中最大的</span> cout <span class="token operator"><<</span> <span class="token operator">*</span>s<span class="token punctuation">.</span><span class="token function">upper_bound</span><span class="token punctuation">(</span><span class="token number">7</span><span class="token punctuation">)</span> <span class="token operator"><<</span> endl<span class="token punctuation">;</span><span class="token comment">//大于等于7中最小的</span> <span class="token keyword">return</span> <span class="token number">0</span><span class="token punctuation">;</span><span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="6-map-x2F-unordered-map"><a href="#6-map-x2F-unordered-map" class="headerlink" title="6.map/unordered_map"></a>6.map/unordered_map</h2><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp"><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><iostream></span></span><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><map></span></span><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><unordered_map></span></span><span class="token keyword">using</span> <span class="token keyword">namespace</span> std<span class="token punctuation">;</span><span class="token keyword">int</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> map<span class="token operator"><</span>string<span class="token punctuation">,</span> <span class="token keyword">int</span><span class="token operator">></span> m<span class="token punctuation">;</span> <span class="token comment">//定义一个空的 map，键是string类型，值是int类型</span> m<span class="token punctuation">[</span><span class="token string">"hello"</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token number">2</span><span class="token punctuation">;</span> <span class="token comment">//将 key是"hello", 值是2的键值对存入 map中</span> cout <span class="token operator"><<</span> m<span class="token punctuation">[</span><span class="token string">"hello"</span><span class="token punctuation">]</span> <span class="token operator"><<</span> endl<span class="token punctuation">;</span> <span class="token comment">//访问map中key为"hello"的value，如果 key不存在，则返回0,在这之后，这个key就存在了</span> cout <span class="token operator"><<</span> m<span class="token punctuation">[</span><span class="token string">"world"</span><span class="token punctuation">]</span> <span class="token operator"><<</span> endl<span class="token punctuation">;</span> m<span class="token punctuation">[</span><span class="token string">"world"</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token number">3</span><span class="token punctuation">;</span> m<span class="token punctuation">[</span><span class="token string">"aaa"</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token number">77</span><span class="token punctuation">;</span> m<span class="token punctuation">[</span><span class="token string">"bbb"</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token number">999</span><span class="token punctuation">;</span> <span class="token comment">//使用迭代器遍历，输出 map 中的所有元素，键用it->first获取，值用it->second获取</span> <span class="token keyword">for</span><span class="token punctuation">(</span><span class="token keyword">auto</span> it <span class="token operator">=</span> m<span class="token punctuation">.</span><span class="token function">begin</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> it <span class="token operator">!=</span> m<span class="token punctuation">.</span><span class="token function">end</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> it<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> cout <span class="token operator"><<</span> it <span class="token operator">-></span> first <span class="token operator"><<</span> <span class="token string">" "</span> <span class="token operator"><<</span> it <span class="token operator">-></span> second <span class="token operator"><<</span> endl<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token comment">//访问 map 的第一个元素，输出它的键和值</span> cout <span class="token operator"><<</span> m<span class="token punctuation">.</span><span class="token function">begin</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">-></span> first <span class="token operator"><<</span> <span class="token string">" "</span> <span class="token operator"><<</span> m<span class="token punctuation">.</span><span class="token function">begin</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">-></span> second <span class="token operator"><<</span> endl<span class="token punctuation">;</span> <span class="token comment">//访问map的最后一个元素，输出它的键和值</span> cout <span class="token operator"><<</span> m<span class="token punctuation">.</span><span class="token function">rbegin</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">-></span> first <span class="token operator"><<</span> <span class="token string">" "</span> <span class="token operator"><<</span> m<span class="token punctuation">.</span><span class="token function">rbegin</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">-></span> second <span class="token operator"><<</span> endl<span class="token punctuation">;</span> <span class="token comment">//输出map的元素个数</span> cout <span class="token operator"><<</span> m<span class="token punctuation">.</span><span class="token function">size</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator"><<</span> endl<span class="token punctuation">;</span> <span class="token comment">//对于有序的map</span> map<span class="token operator"><</span>string<span class="token punctuation">,</span> <span class="token keyword">int</span><span class="token operator">></span> mm<span class="token punctuation">;</span> <span class="token comment">//key是升序的a,b,c,d</span> map<span class="token operator"><</span>string<span class="token punctuation">,</span> <span class="token keyword">int</span><span class="token punctuation">,</span> greater<span class="token operator"><</span>string<span class="token operator">>></span> mmm<span class="token punctuation">;</span><span class="token comment">//key是降序的c,b,a</span> <span class="token comment">//end()是最后一个元素的后一个，是空。rbegin()才是最后一个元素</span> <span class="token keyword">return</span> <span class="token number">0</span><span class="token punctuation">;</span><span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="7-stack"><a href="#7-stack" class="headerlink" title="7.stack"></a>7.stack</h2><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp"><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><iostream></span></span><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><stack></span></span><span class="token keyword">using</span> <span class="token keyword">namespace</span> std<span class="token punctuation">;</span><span class="token keyword">int</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> stack<span class="token operator"><</span><span class="token keyword">int</span><span class="token operator">></span> s<span class="token punctuation">;</span> <span class="token comment">//定义一个空栈</span> <span class="token keyword">for</span><span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> <span class="token number">6</span><span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> s<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span>i<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//将元素i压入栈s中</span> <span class="token punctuation">}</span> cout <span class="token operator"><<</span> s<span class="token punctuation">.</span><span class="token function">top</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator"><<</span> endl<span class="token punctuation">;</span> <span class="token comment">//访问s的栈顶元素</span> cout <span class="token operator"><<</span> s<span class="token punctuation">.</span><span class="token function">size</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator"><<</span> endl<span class="token punctuation">;</span> <span class="token comment">//输出s的元素个数</span> s<span class="token punctuation">.</span><span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//移除栈顶元素</span> <span class="token keyword">return</span> <span class="token number">0</span><span class="token punctuation">;</span><span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="8-queue"><a href="#8-queue" class="headerlink" title="8.queue"></a>8.queue</h2><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp"><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><iostream></span></span><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><queue></span></span><span class="token keyword">using</span> <span class="token keyword">namespace</span> std<span class="token punctuation">;</span><span class="token keyword">int</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> queue<span class="token operator"><</span><span class="token keyword">int</span><span class="token operator">></span> q<span class="token punctuation">;</span><span class="token comment">//定义一个空栈</span> <span class="token keyword">for</span><span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> <span class="token number">6</span><span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> q<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span>i<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//将i的值依次压入到队列q中</span> <span class="token punctuation">}</span> cout <span class="token operator"><<</span> q<span class="token punctuation">.</span><span class="token function">front</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator"><<</span> <span class="token string">""</span> <span class="token operator"><<</span> q<span class="token punctuation">.</span><span class="token function">back</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator"><<</span> endl<span class="token punctuation">;</span><span class="token comment">//访问队首和队尾元素</span> cout<span class="token operator"><<</span> q<span class="token punctuation">.</span><span class="token function">size</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator"><<</span> endl<span class="token punctuation">;</span> <span class="token comment">//输出队列的元素个数</span> q<span class="token punctuation">.</span><span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//移除队列的队首元素</span> <span class="token keyword">return</span> <span class="token number">0</span><span class="token punctuation">;</span><span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="9-排序"><a href="#9-排序" class="headerlink" title="9.排序"></a>9.排序</h2><pre class="line-numbers language-cpp" data-language="cpp"><code class="language-cpp"><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><iostream></span></span><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><vector></span></span><span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">include</span><span class="token string"><algorithm></span></span><span class="token keyword">using</span> <span class="token keyword">namespace</span> std<span class="token punctuation">;</span><span class="token keyword">bool</span> <span class="token function">cmp</span><span class="token punctuation">(</span><span class="token keyword">int</span> a<span class="token punctuation">,</span> <span class="token keyword">int</span> b<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">return</span> a <span class="token operator">></span> b<span class="token punctuation">;</span><span class="token comment">//从大到小排序</span><span class="token punctuation">}</span><span class="token keyword">int</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> vector<span class="token operator"><</span><span class="token keyword">int</span><span class="token operator">></span> <span class="token function">v</span><span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">for</span><span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> <span class="token number">10</span><span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> cin <span class="token operator">>></span> v<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token function">sort</span><span class="token punctuation">(</span>v<span class="token punctuation">.</span><span class="token function">begin</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> v<span class="token punctuation">.</span><span class="token function">end</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//默认，从小到大排序</span> <span class="token keyword">int</span> arr<span class="token punctuation">[</span><span class="token number">10</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> <span class="token number">10</span><span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> cin <span class="token operator">>></span> arr<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token function">sort</span><span class="token punctuation">(</span>arr<span class="token punctuation">,</span> arr <span class="token operator">+</span> <span class="token number">10</span><span class="token punctuation">,</span> cmp<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//arr从大到小排列</span> <span class="token keyword">return</span> <span class="token number">0</span><span class="token punctuation">;</span><span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="10-其他"><a href="#10-其他" class="headerlink" title="10.其他"></a>10.其他</h2><p>auto 自动推断变量类型，用在迭代器里</p><pre class="line-numbers language-CPP" data-language="CPP"><code class="language-CPP">基于范围的for循环int arr[4] = {0, 1, 2, 3};for (int i : arr)cout << i << endl; // 输出数组中的每⼀个元素的值，每个元素占据⼀⾏// i 依次表示数组中的每⼀个元素，此时read onlyfor (int &i : arr) // i为引⽤变量i = i * 2; // 将数组中的每⼀个元素都乘以2，arr[4]的内容变为了{0, 2, 4, 6}<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>类型转换</p><pre class="line-numbers language-CPP" data-language="CPP"><code class="language-CPP">to_string stoi stodstof (string to float)stold (string to long double)stol (string to long)stoll (string to long long)stoul(string to unsigned long)stoull (string to unsigned long long)<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre>]]></content>
<categories>
<category> 小知识 </category>
</categories>
<tags>
<tag> C++ </tag>
<tag> 算法 </tag>
<tag> 小知识 </tag>
</tags>
</entry>
<entry>
<title>Java刷题API</title>
<link href="/2024/05/07/java-shua-ti-api/"/>
<url>/2024/05/07/java-shua-ti-api/</url>
<content type="html"><![CDATA[<p><img src="/2024/05/07/java-shua-ti-api/1.png" alt="图片一览"></p><h2 id="0：输入输出"><a href="#0：输入输出" class="headerlink" title="0：输入输出"></a>0：输入输出</h2><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>util<span class="token punctuation">.</span></span><span class="token class-name">Scanner</span></span><span class="token punctuation">;</span><span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Solution</span> <span class="token punctuation">{</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token class-name">Scanner</span> scanner <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Scanner</span><span class="token punctuation">(</span><span class="token class-name">System</span><span class="token punctuation">.</span>in<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//方法1：一般用来接收数组。以空格分界</span> <span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> ints <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token keyword">int</span><span class="token punctuation">[</span><span class="token number">5</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> <span class="token keyword">while</span> <span class="token punctuation">(</span>scanner<span class="token punctuation">.</span><span class="token function">hasNext</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span> num <span class="token operator">=</span> scanner<span class="token punctuation">.</span><span class="token function">nextInt</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">if</span> <span class="token punctuation">(</span>num <span class="token operator">==</span> <span class="token operator">-</span><span class="token number">1</span><span class="token punctuation">)</span> <span class="token keyword">break</span><span class="token punctuation">;</span> ints<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator">=</span> num<span class="token punctuation">;</span> <span class="token comment">/*或者*/</span> <span class="token class-name">String</span> next <span class="token operator">=</span> scanner<span class="token punctuation">.</span><span class="token function">next</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token comment">//方法2：一般用来接受字符串,以换行符分界</span> <span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> arr <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">String</span><span class="token punctuation">[</span><span class="token number">5</span><span class="token punctuation">]</span><span class="token punctuation">;</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> <span class="token keyword">while</span> <span class="token punctuation">(</span>scanner<span class="token punctuation">.</span><span class="token function">hasNextLine</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token class-name">String</span> str <span class="token operator">=</span> scanner<span class="token punctuation">.</span><span class="token function">nextLine</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">if</span> <span class="token punctuation">(</span>str <span class="token operator">==</span> <span class="token string">""</span><span class="token punctuation">)</span> <span class="token keyword">break</span><span class="token punctuation">;</span> arr<span class="token punctuation">[</span>i<span class="token operator">++</span><span class="token punctuation">]</span> <span class="token operator">=</span> str<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span><span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="一：Integer-类"><a href="#一：Integer-类" class="headerlink" title="一：Integer 类"></a>一：Integer 类</h2><p>1.String -> int：int value = Integer.parseInt(str);<br>2.将二进制字符串str转换成int： int binary = Integer.parseInt(str,2);//“111”->7<br>3.十进制int转二进制字符串：String binaryN=Integer.toBinaryString(N);//15 -> “1111”</p><h2 id="二：String-类"><a href="#二：String-类" class="headerlink" title="二：String 类"></a>二：String 类</h2><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">StringExample</span> <span class="token punctuation">{</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token class-name">String</span> s <span class="token operator">=</span> <span class="token string">"hel"</span><span class="token operator">+</span><span class="token string">"lo"</span><span class="token punctuation">;</span><span class="token comment">//连接</span> <span class="token keyword">int</span> len <span class="token operator">=</span> s<span class="token punctuation">.</span><span class="token function">length</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">char</span> c <span class="token operator">=</span> s<span class="token punctuation">.</span><span class="token function">charAt</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//返回指定字符在此字符串中第一次出现处的索引,找不到返回-1</span> <span class="token keyword">int</span> index1 <span class="token operator">=</span> s<span class="token punctuation">.</span><span class="token function">indexOf</span><span class="token punctuation">(</span><span class="token string">"el"</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//1</span> <span class="token class-name">String</span> substr <span class="token operator">=</span> s<span class="token punctuation">.</span><span class="token function">substring</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//hel,前闭后开</span> <span class="token class-name">String</span> s2 <span class="token operator">=</span> <span class="token string">"Hi,Linda,Hello"</span><span class="token punctuation">;</span> <span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> ss <span class="token operator">=</span> s2<span class="token punctuation">.</span><span class="token function">split</span><span class="token punctuation">(</span><span class="token string">","</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//分割</span> <span class="token comment">//和Integer的相互转换</span> <span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token class-name">Integer</span><span class="token punctuation">.</span><span class="token function">parseInt</span><span class="token punctuation">(</span><span class="token string">"24"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token class-name">String</span> string <span class="token operator">=</span> <span class="token class-name">Integer</span><span class="token punctuation">.</span><span class="token function">toString</span><span class="token punctuation">(</span>i<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//和Long的相互转换</span> <span class="token keyword">long</span> ll <span class="token operator">=</span> <span class="token class-name">Long</span><span class="token punctuation">.</span><span class="token function">parseLong</span><span class="token punctuation">(</span><span class="token string">"25"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> string <span class="token operator">=</span> <span class="token class-name">Long</span><span class="token punctuation">.</span><span class="token function">toString</span><span class="token punctuation">(</span>ll<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//和char[]的相互转换</span> <span class="token keyword">char</span><span class="token punctuation">[</span><span class="token punctuation">]</span> cc <span class="token operator">=</span> string<span class="token punctuation">.</span><span class="token function">toCharArray</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> string <span class="token operator">=</span> <span class="token class-name">String</span><span class="token punctuation">.</span><span class="token function">valueOf</span><span class="token punctuation">(</span>cc<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//字符串是否相等</span> <span class="token class-name">String</span> str1 <span class="token operator">=</span> <span class="token string">"hello"</span><span class="token punctuation">,</span>str2 <span class="token operator">=</span> <span class="token string">"hello"</span><span class="token punctuation">;</span> <span class="token keyword">if</span> <span class="token punctuation">(</span>str1<span class="token punctuation">.</span><span class="token function">equals</span><span class="token punctuation">(</span>str2<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token boolean">true</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//替换</span> str1<span class="token punctuation">.</span><span class="token function">replace</span><span class="token punctuation">(</span><span class="token string">"1"</span><span class="token punctuation">,</span><span class="token string">"a"</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//将1替换为a</span> <span class="token comment">//去除头尾空格</span> str1 <span class="token operator">=</span> str1<span class="token punctuation">.</span><span class="token function">trim</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="三：数组"><a href="#三：数组" class="headerlink" title="三：数组"></a>三：数组</h2><p>关于多重数组【重点】</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">[</span><span class="token punctuation">]</span> nums <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token punctuation">{</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">1</span><span class="token punctuation">}</span><span class="token punctuation">,</span> <span class="token punctuation">{</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token number">2</span><span class="token punctuation">}</span><span class="token punctuation">,</span> <span class="token punctuation">{</span><span class="token number">3</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">}</span><span class="token punctuation">}</span><span class="token punctuation">;</span> <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>nums<span class="token punctuation">.</span>length<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//3,一共有多少行</span> <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>nums<span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span><span class="token punctuation">.</span>length<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//2,第0行的长度</span><span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>util<span class="token punctuation">.</span></span><span class="token operator">*</span></span><span class="token punctuation">;</span><span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">ArrayExample</span> <span class="token punctuation">{</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> arr <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token keyword">int</span><span class="token punctuation">[</span><span class="token number">10</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> arr2 <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">4</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">,</span><span class="token number">7</span><span class="token punctuation">,</span><span class="token number">5</span><span class="token punctuation">}</span><span class="token punctuation">;</span> <span class="token comment">//全部填充</span> <span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">fill</span><span class="token punctuation">(</span>arr<span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">toString</span><span class="token punctuation">(</span>arr<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//[3, 3, 3, 3, 3, 3, 3, 3, 3, 3]</span> <span class="token comment">//排序,默认从小到大</span> <span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">sort</span><span class="token punctuation">(</span>arr2<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">toString</span><span class="token punctuation">(</span>arr2<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//arr2:[1 3 4 5 7 ]</span> <span class="token comment">//排序，从大到小,lambda方法</span> <span class="token class-name">Integer</span><span class="token punctuation">[</span><span class="token punctuation">]</span> arr3 <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token number">3</span><span class="token punctuation">,</span><span class="token number">6</span><span class="token punctuation">,</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">8</span><span class="token punctuation">}</span><span class="token punctuation">;</span> <span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">sort</span><span class="token punctuation">(</span>arr3<span class="token punctuation">,</span> <span class="token punctuation">(</span>a<span class="token punctuation">,</span> b<span class="token punctuation">)</span> <span class="token operator">-></span> b <span class="token operator">-</span> a<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">toString</span><span class="token punctuation">(</span>arr3<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//[8, 6, 3, 2, 1]</span> <span class="token comment">//排序，从大到小，匿名类</span> <span class="token class-name">Integer</span><span class="token punctuation">[</span><span class="token punctuation">]</span> arr4 <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token number">3</span><span class="token punctuation">,</span><span class="token number">6</span><span class="token punctuation">,</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">8</span><span class="token punctuation">}</span><span class="token punctuation">;</span> <span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">sort</span><span class="token punctuation">(</span>arr4<span class="token punctuation">,</span> <span class="token keyword">new</span> <span class="token class-name">Comparator</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token annotation punctuation">@Override</span> <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">compare</span><span class="token punctuation">(</span><span class="token class-name">Integer</span> o1<span class="token punctuation">,</span> <span class="token class-name">Integer</span> o2<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">return</span> o2 <span class="token operator">-</span> o1<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">toString</span><span class="token punctuation">(</span>arr4<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//[8, 6, 3, 2, 1]</span> <span class="token punctuation">}</span><span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="四：动态数组（ArrayList）"><a href="#四：动态数组（ArrayList）" class="headerlink" title="四：动态数组（ArrayList）"></a>四：动态数组（ArrayList）</h2><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>util<span class="token punctuation">.</span></span><span class="token operator">*</span></span><span class="token punctuation">;</span><span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">ArrayListExample</span> <span class="token punctuation">{</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token comment">//初始化空的list</span> <span class="token class-name">ArrayList</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> a1 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ArrayList</span><span class="token generics"><span class="token punctuation"><</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//另一种初始化方式,不过是List，不是ArrayList</span> <span class="token class-name">List</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> a2 <span class="token operator">=</span> <span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">asList</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">5</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">7</span><span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//填充</span> <span class="token class-name">Collections</span><span class="token punctuation">.</span><span class="token function">fill</span><span class="token punctuation">(</span>a2<span class="token punctuation">,</span> <span class="token number">100</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//将a2全部元素设置为100</span> <span class="token comment">//增删</span> a1<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">,</span><span class="token number">4</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//将4插入到第三个位置</span> a1<span class="token punctuation">.</span><span class="token function">remove</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//删除下标为0的</span> <span class="token comment">//遍历</span> <span class="token comment">//1.下标</span> <span class="token keyword">for</span><span class="token punctuation">(</span><span class="token keyword">int</span> i<span class="token operator">=</span><span class="token number">0</span><span class="token punctuation">;</span>i<span class="token operator"><</span>a1<span class="token punctuation">.</span><span class="token function">size</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>i<span class="token operator">++</span><span class="token punctuation">)</span><span class="token punctuation">{</span> a1<span class="token punctuation">.</span><span class="token function">get</span><span class="token punctuation">(</span>i<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//访问下标为i的</span> <span class="token punctuation">}</span> <span class="token comment">//2.循环</span> <span class="token keyword">for</span><span class="token punctuation">(</span><span class="token keyword">int</span> item<span class="token operator">:</span>a1<span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token punctuation">}</span> <span class="token comment">//排序</span> <span class="token class-name">Collections</span><span class="token punctuation">.</span><span class="token function">sort</span><span class="token punctuation">(</span>a2<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//排序</span> <span class="token class-name">Collections</span><span class="token punctuation">.</span><span class="token function">max</span><span class="token punctuation">(</span>a2<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//最大值</span> <span class="token class-name">Collections</span><span class="token punctuation">.</span><span class="token function">min</span><span class="token punctuation">(</span>a2<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//最小值</span> <span class="token comment">//翻转</span> <span class="token class-name">Collections</span><span class="token punctuation">.</span><span class="token function">reverse</span><span class="token punctuation">(</span>a2<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="五：栈Stack"><a href="#五：栈Stack" class="headerlink" title="五：栈Stack"></a>五：栈Stack</h2><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>util<span class="token punctuation">.</span></span><span class="token operator">*</span></span><span class="token punctuation">;</span><span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">StackExample</span> <span class="token punctuation">{</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token class-name">Stack</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> stack <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Stack</span><span class="token generics"><span class="token punctuation"><</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> stack<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span> stack<span class="token punctuation">.</span><span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//移除堆栈顶部的对象，并作为此函数的值返回该对象</span> stack<span class="token punctuation">.</span><span class="token function">peek</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//查看堆栈顶部的对象，但不从堆栈中移除它</span> <span class="token comment">//注意：另一方面，不推荐使用Stack(),应该使用Deque(双端队列)</span> <span class="token class-name">Deque</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> stack1 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ArrayDeque</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> stack1<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">;</span> stack1<span class="token punctuation">.</span><span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> stack1<span class="token punctuation">.</span><span class="token function">peek</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="六：队列Queue"><a href="#六：队列Queue" class="headerlink" title="六：队列Queue"></a>六：队列Queue</h2><h3 id="单向队列Queue"><a href="#单向队列Queue" class="headerlink" title="单向队列Queue"></a>单向队列Queue</h3><pre class="line-numbers language-none"><code class="language-none">Queue<Integer> q = new LinkedList<>(); //实例化 offer(E e); // 队尾加入元素e。 若成功入队返回值true，否则返回false --- O(1) poll(); // 出队头，返回出队元素e --- O(1) peek(); // 查看队头元素， 返回值队首元素e --- O(1) isEmpty() // 若队空返回true， 否则返回false --- O(1) size() // 返回队中元素个数 --- O(1)<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token class-name">Queue</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> queue <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ArrayDeque</span><span class="token generics"><span class="token punctuation"><</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//Queue<Integer> q = new LinkedList<>();</span>queue<span class="token punctuation">.</span><span class="token function">offer</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token keyword">int</span> a <span class="token operator">=</span> queue<span class="token punctuation">.</span><span class="token function">peek</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//返回第一个元素</span><span class="token keyword">int</span> b <span class="token operator">=</span> queue<span class="token punctuation">.</span><span class="token function">poll</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//删除并返回第一个元素</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span></span></code></pre><h3 id="双向队列Deque"><a href="#双向队列Deque" class="headerlink" title="双向队列Deque"></a>双向队列Deque</h3><p>Queue有一个子接口<code>Dueue</code>，即双向队列，和单向队列不同，它的出队入队可以从两个方向。</p><pre class="line-numbers language-none"><code class="language-none">Dueue<Integer> q = new LinkedList<>(); //实例化 offFirst(Object e) // 将指定元素添加到双端队列的头部 --- O(1) offLast(Object e) //将指定元素添加到双端队列的尾部 --- O(1) pollFirst() //获取并删除双端队列的第一个元素 --- O(1) pollLast() //获取并删除双端队列的最后一个元素 --- O(1) peekFirst() //获取但不删除双端队列的第一个元素 --- O(1) peekLast() //获取但不删除双端队列的最后一个元素 --- O(1) isEmpty() //非空返回true，否则返回false size() //队列中元素个数<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="七：Map-对象"><a href="#七：Map-对象" class="headerlink" title="七：Map 对象"></a>七：Map 对象</h2><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>util<span class="token punctuation">.</span></span><span class="token operator">*</span></span><span class="token punctuation">;</span><span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">MapExample</span> <span class="token punctuation">{</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token class-name">Map</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">String</span><span class="token punctuation">,</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> map <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">HashMap</span><span class="token generics"><span class="token punctuation"><</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> map<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span><span class="token string">"Linda"</span><span class="token punctuation">,</span><span class="token number">18</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//增加</span> <span class="token keyword">boolean</span> isContain <span class="token operator">=</span> map<span class="token punctuation">.</span><span class="token function">containsKey</span><span class="token punctuation">(</span><span class="token string">"Linda"</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//时间复杂度O(1)</span> <span class="token keyword">boolean</span> isContain2 <span class="token operator">=</span> map<span class="token punctuation">.</span><span class="token function">containsValue</span><span class="token punctuation">(</span><span class="token number">18</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">int</span> age <span class="token operator">=</span> map<span class="token punctuation">.</span><span class="token function">get</span><span class="token punctuation">(</span><span class="token string">"Linda"</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//18</span> <span class="token keyword">int</span> age2 <span class="token operator">=</span> map<span class="token punctuation">.</span><span class="token function">getOrDefault</span><span class="token punctuation">(</span><span class="token string">"Bob"</span><span class="token punctuation">,</span><span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//含有默认值</span> map<span class="token punctuation">.</span><span class="token function">remove</span><span class="token punctuation">(</span><span class="token string">"Linda"</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//移除</span> <span class="token comment">//遍历map键值对</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token class-name">Map<span class="token punctuation">.</span>Entry</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">String</span><span class="token punctuation">,</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> entry<span class="token operator">:</span>map<span class="token punctuation">.</span><span class="token function">entrySet</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token class-name">String</span> key <span class="token operator">=</span> entry<span class="token punctuation">.</span><span class="token function">getKey</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token class-name">Integer</span> value <span class="token operator">=</span> entry<span class="token punctuation">.</span><span class="token function">getValue</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token comment">//遍历key</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token class-name">String</span> key<span class="token operator">:</span>map<span class="token punctuation">.</span><span class="token function">keySet</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>key<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token comment">//遍历value</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token class-name">Integer</span> value<span class="token operator">:</span>map<span class="token punctuation">.</span><span class="token function">values</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>value<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span><span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="八：Set-对象"><a href="#八：Set-对象" class="headerlink" title="八：Set 对象"></a>八：Set 对象</h2><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>util<span class="token punctuation">.</span></span><span class="token operator">*</span></span><span class="token punctuation">;</span><span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">SetExample</span> <span class="token punctuation">{</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token class-name">Set</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> set <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">HashSet</span><span class="token generics"><span class="token punctuation"><</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//创建</span> set<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token number">23</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//增加</span> <span class="token keyword">boolean</span> isContain <span class="token operator">=</span> set<span class="token punctuation">.</span><span class="token function">contains</span><span class="token punctuation">(</span><span class="token number">15</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//是否包含</span> set<span class="token punctuation">.</span><span class="token function">remove</span><span class="token punctuation">(</span><span class="token number">23</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//移除</span> <span class="token comment">//遍历set</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token class-name">Integer</span> item <span class="token operator">:</span> set<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>item<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token comment">//清除</span> set<span class="token punctuation">.</span><span class="token function">clear</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token comment">//T</span><span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>util<span class="token punctuation">.</span></span><span class="token class-name">TreeSet</span></span><span class="token punctuation">;</span><span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">TreeSetExample</span> <span class="token punctuation">{</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token class-name">TreeSet</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> set <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">TreeSet</span><span class="token generics"><span class="token punctuation"><</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> <span class="token number">12</span><span class="token punctuation">;</span> i <span class="token operator">+=</span> <span class="token number">2</span><span class="token punctuation">)</span> set<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>i<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token class-name">Integer</span> floor <span class="token operator">=</span> set<span class="token punctuation">.</span><span class="token function">floor</span><span class="token punctuation">(</span><span class="token number">7</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//6,向下取整，包括自身 <=7</span> <span class="token class-name">Integer</span> ceiling <span class="token operator">=</span> set<span class="token punctuation">.</span><span class="token function">ceiling</span><span class="token punctuation">(</span><span class="token number">5</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//6,向上取值，包括自身 >=5</span> <span class="token punctuation">}</span><span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="九：优先队列PriorityQueue"><a href="#九：优先队列PriorityQueue" class="headerlink" title="九：优先队列PriorityQueue"></a>九：优先队列PriorityQueue</h2><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token function">offer</span><span class="token punctuation">(</span><span class="token class-name">E</span> e<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">// 在堆中加入元素e，并调整堆。若成功入堆返回值true，否则返回false --- O(logN)</span> <span class="token function">poll</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">// 弹出堆顶元素，并重新调整堆，返回出队元素e --- O(logN)</span> <span class="token function">peek</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">// 查看堆顶元素， 返回值堆顶元素e --- O(1)j</span> <span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//判断队列是否为空</span> <span class="token function">size</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//队列中元素数量</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>util<span class="token punctuation">.</span></span><span class="token operator">*</span></span><span class="token punctuation">;</span><span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">PriorityQueueExample</span> <span class="token punctuation">{</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token class-name">PriorityQueue</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> minH <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">PriorityQueue</span><span class="token generics"><span class="token punctuation"><</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//小根堆</span> <span class="token class-name">PriorityQueue</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> maxH <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">PriorityQueue</span><span class="token generics"><span class="token punctuation"><</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span>b<span class="token punctuation">)</span> <span class="token operator">-></span> b<span class="token operator">-</span>a<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//大根堆</span> <span class="token class-name">PriorityQueue</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> pq2 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">PriorityQueue</span><span class="token generics"><span class="token punctuation"><</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">Comparator</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token annotation punctuation">@Override</span> <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">compare</span><span class="token punctuation">(</span><span class="token class-name">Integer</span> o1<span class="token punctuation">,</span> <span class="token class-name">Integer</span> o2<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">return</span> o2 <span class="token operator">-</span> o1<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="十：保留小数有效数字（四舍五入）"><a href="#十：保留小数有效数字（四舍五入）" class="headerlink" title="十：保留小数有效数字（四舍五入）"></a>十：保留小数有效数字（四舍五入）</h2><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>math<span class="token punctuation">.</span></span><span class="token operator">*</span></span><span class="token punctuation">;</span><span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">BigDecimalExample</span> <span class="token punctuation">{</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">double</span> a <span class="token operator">=</span> <span class="token number">2.5111</span><span class="token punctuation">;</span> <span class="token class-name">BigDecimal</span> decimal <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">BigDecimal</span><span class="token punctuation">(</span>a<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">setScale</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">,</span> <span class="token class-name">RoundingMode</span><span class="token punctuation">.</span>HALF_UP<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>decimal<span class="token punctuation">.</span><span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token punctuation">}</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h2 id="十一：长度计算"><a href="#十一：长度计算" class="headerlink" title="十一：长度计算"></a>十一：长度计算</h2><p>length属性是<strong>针对数组</strong>说的，比如说你声明了一个数组，想知道这个数组的长度则用到了length这个属性。<br>length()方法是<strong>针对字符串String</strong>说的，如果想看这个字符串的长度则用到length()这个方法。<br>size()方法是<strong>针对泛型集合泛型集合(Collection)如Set、List、Map</strong>说的，如果想看这个泛型有多少个元素，就调用此方法来查看。数组没有size()方法。</p><h2 id="工具类"><a href="#工具类" class="headerlink" title="工具类"></a>工具类</h2><h3 id="1、java-util-Math：主要包含数学内的应用方法"><a href="#1、java-util-Math：主要包含数学内的应用方法" class="headerlink" title="1、java.util.Math：主要包含数学内的应用方法"></a>1、java.util.Math：主要包含数学内的应用方法</h3><p>（1）Math.abs(参数)</p><p>作用：返回参数的绝对值</p><p>参数可以是 int，float，long，double等类型，返回值类型同参数类型。（参数也可以是short，byte，但是返回类型会转成int）</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token class-name">Math</span><span class="token punctuation">.</span><span class="token function">abs</span><span class="token punctuation">(</span><span class="token keyword">double</span> a<span class="token punctuation">)</span><span class="token punctuation">;</span> <span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>（2）Math.max(参数1，参数2)，Math.min(参数1，参数2)</p><p>作用：返回两个参数的最大值，最小值。</p><p>参数可以是 int，float，long，double等类型，返回值类型同参数类型。（参数也可以是short，byte，但是返回类型会转成int）</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token class-name">Math</span><span class="token punctuation">.</span><span class="token function">max</span><span class="token punctuation">(</span><span class="token keyword">long</span> a<span class="token punctuation">,</span> <span class="token keyword">long</span> b<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//返回两个参数中较大的值</span><span class="token class-name">Math</span><span class="token punctuation">.</span><span class="token function">min</span><span class="token punctuation">(</span><span class="token keyword">long</span> a<span class="token punctuation">,</span> <span class="token keyword">long</span> b<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//返回两个参数中较小的值</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><p>（3）Math.sqrt(参数)、Math.cbrt(参数)</p><p>作用：开平方，开立方</p><p>参数可以是 int，float，long，double，short，byte等类型，返回值类型为double。</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token class-name">Math</span><span class="token punctuation">.</span><span class="token function">sqrt</span><span class="token punctuation">(</span><span class="token keyword">long</span> a<span class="token punctuation">)</span> <span class="token comment">//开平方</span><span class="token class-name">Math</span><span class="token punctuation">.</span><span class="token function">cbrt</span><span class="token punctuation">(</span><span class="token keyword">long</span> b<span class="token punctuation">)</span> <span class="token comment">//开立方</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><p>（4）Math.pow(参数1，参数2）</p><p>作用：返回参数1的参数2次方。</p><p>参数可以是 int，float，long，double，short，byte等类型，返回值类型为double。</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token class-name">Math</span><span class="token punctuation">.</span><span class="token function">pow</span><span class="token punctuation">(</span><span class="token keyword">double</span> a<span class="token punctuation">,</span> <span class="token keyword">double</span> b<span class="token punctuation">)</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>（5）Math.ceil(参数)</p><p>作用：对浮点数向上取整。</p><p>参数可以是 int，float，long，double，short，byte等类型，返回值类型为double。</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token class-name">Math</span><span class="token punctuation">.</span><span class="token function">ceil</span><span class="token punctuation">(</span><span class="token keyword">double</span> a<span class="token punctuation">)</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>（6）Math.floor(参数)</p><p>作用：对浮点数向下取整。</p><p>参数可以是 int，float，long，double，short，byte等类型，返回值类型为double。</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token class-name">Math</span><span class="token punctuation">.</span><span class="token function">floor</span><span class="token punctuation">(</span><span class="token keyword">double</span> a<span class="token punctuation">)</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p> （7）Math.round(参数)</p><p>作用：对浮点数四舍五入。</p><p>参数可以是 int，float，long，double，short，byte等类型，返回值类型为int或者long。</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token class-name">Math</span><span class="token punctuation">.</span><span class="token function">round</span><span class="token punctuation">(</span><span class="token keyword">double</span> a<span class="token punctuation">)</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>（8）Math.log(参数），Math.log10(参数)</p><p>作用：取对数。</p><p>参数可以是 int，float，long，double，short，byte等类型，返回值类型为double。</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token class-name">Math</span><span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token keyword">double</span> a<span class="token punctuation">)</span> <span class="token comment">//以e为底取对数</span><span class="token class-name">Math</span><span class="token punctuation">.</span><span class="token function">log10</span><span class="token punctuation">(</span><span class="token keyword">double</span> b<span class="token punctuation">)</span> <span class="token comment">//以10为底取对数</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><p> 那么，以m为底取N的对数该如何求呢？</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token comment">//注意：logmN：以m为底取N的对数。</span><span class="token class-name">Math</span><span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token number">8</span><span class="token punctuation">)</span><span class="token operator">/</span><span class="token class-name">Math</span><span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//该代码意为：以2为底取8的对数为：3。</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><p>（9）Math.random()</p><p>作用：返回一个随机数，随机数范围为[0，1)，左闭右开。返回值类型为double。</p><h3 id="2、java-util-Arrays：主要包含了操作数组的各种方法"><a href="#2、java-util-Arrays：主要包含了操作数组的各种方法" class="headerlink" title="2、java.util.Arrays：主要包含了操作数组的各种方法"></a>2、java.util.Arrays：主要包含了操作数组的各种方法</h3><p>（1）Arrays.toString(arr)</p><p>作用：返回字符串，便于打印数组内容</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token class-name">String</span> str <span class="token operator">=</span> <span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">toString</span><span class="token punctuation">(</span>arr<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">// Arrays类的toString()方法能将数组中的内容全部打印出来</span><span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">print</span><span class="token punctuation">(</span>str<span class="token punctuation">)</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><p>（2）Arrays.sort(arr，fromIndex，toIndex)</p><p>作用：数组升序</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> a <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">{</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">4</span><span class="token punctuation">,</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">,</span><span class="token number">5</span><span class="token punctuation">}</span><span class="token punctuation">;</span><span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">sort</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span><span class="token number">0</span><span class="token punctuation">,</span><span class="token number">5</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//默认对全部元素升序，对下标0到下标为5-1的5个元素进行排序。</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><p>（3）Arrays.sort(arr，fromIndex，toIndex，Collections.reverseOrder())</p><p>作用：数组降序</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">sort</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">,</span><span class="token class-name">Collections</span><span class="token punctuation">.</span><span class="token function">reverseOrder</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p> （4）Arrays.equals()</p><p>作用：比较数组元素</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> arr1 <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">}</span><span class="token punctuation">;</span><span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> arr2 <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">}</span><span class="token punctuation">;</span><span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">equals</span><span class="token punctuation">(</span>arr1<span class="token punctuation">,</span>arr2<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//输出：true</span><span class="token comment">//如果是arr1.equals(arr2),则返回false，因为equals比较的是两个对象的地址，不是里面的数，而Arrays.equals重写了equals，所以，这里能比较元素是否相等。</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span></span></code></pre><p>（5）Arrays.copeOf() 和Arrays.copeOfRange() </p><p>作用：截取数组，传回的数组是新的数组对象，改变传回数组中的元素值，不会影响原来的数组。</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> arr <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token number">10</span><span class="token punctuation">,</span><span class="token number">20</span><span class="token punctuation">,</span><span class="token number">30</span><span class="token punctuation">,</span><span class="token number">40</span><span class="token punctuation">,</span><span class="token number">50</span><span class="token punctuation">}</span><span class="token punctuation">;</span><span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> arr1 <span class="token operator">=</span> <span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">copyOf</span><span class="token punctuation">(</span>arr<span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token class-name">String</span> str <span class="token operator">=</span> <span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">toString</span><span class="token punctuation">(</span>arr1<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">// Arrays类的toString()方法能将数组中的内容全部打印出来</span><span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">print</span><span class="token punctuation">(</span>str<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//输出：[10, 20, 30] （截取arr数组的3个元素赋值给新数组arr1）</span><span class="token keyword">int</span> <span class="token punctuation">[</span><span class="token punctuation">]</span>arr <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token number">10</span><span class="token punctuation">,</span><span class="token number">20</span><span class="token punctuation">,</span><span class="token number">30</span><span class="token punctuation">,</span><span class="token number">40</span><span class="token punctuation">,</span><span class="token number">50</span><span class="token punctuation">}</span><span class="token punctuation">;</span><span class="token keyword">int</span> <span class="token punctuation">[</span><span class="token punctuation">]</span>arr1 <span class="token operator">=</span> <span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">copyOfRange</span><span class="token punctuation">(</span>arr<span class="token punctuation">,</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token class-name">String</span> str <span class="token operator">=</span> <span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">toString</span><span class="token punctuation">(</span>arr1<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">// Arrays类的toString()方法能将数组中的内容全部打印出来</span><span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">print</span><span class="token punctuation">(</span>str<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//输出：[20, 30] （从第1位（index=0开始）截取到第3位（不包括）</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h3 id="3、java-util-Collections：主要对集合进行操作"><a href="#3、java-util-Collections：主要对集合进行操作" class="headerlink" title="3、java.util.Collections：主要对集合进行操作"></a>3、java.util.Collections：主要对集合进行操作</h3><p>（1）Collections.sort()</p><p>作用：升序/降序</p><h3 id="4、基本类型的最大值与最小值"><a href="#4、基本类型的最大值与最小值" class="headerlink" title="4、基本类型的最大值与最小值"></a>4、基本类型的最大值与最小值</h3><pre class="line-numbers language-java" data-language="java"><code class="language-java">fmax <span class="token operator">=</span> <span class="token class-name">Float</span><span class="token punctuation">.</span>MAX_VALUE<span class="token punctuation">;</span>fmin <span class="token operator">=</span> <span class="token class-name">Float</span><span class="token punctuation">.</span>MIN_VALUE<span class="token punctuation">;</span>dmax <span class="token operator">=</span> <span class="token class-name">Double</span><span class="token punctuation">.</span>MAX_VALUE<span class="token punctuation">;</span>dmin <span class="token operator">=</span> <span class="token class-name">Double</span><span class="token punctuation">.</span>MIN_VALUE<span class="token punctuation">;</span>bmax <span class="token operator">=</span> <span class="token class-name">Byte</span><span class="token punctuation">.</span>MAX_VALUE<span class="token punctuation">;</span>bmin <span class="token operator">=</span> <span class="token class-name">Byte</span><span class="token punctuation">.</span>MIN_VALUE<span class="token punctuation">;</span>cmax <span class="token operator">=</span> <span class="token class-name">Character</span><span class="token punctuation">.</span>MAX_VALUE<span class="token punctuation">;</span>cmin <span class="token operator">=</span> <span class="token class-name">Character</span><span class="token punctuation">.</span>MIN_VALUE<span class="token punctuation">;</span>shmax <span class="token operator">=</span> <span class="token class-name">Short</span><span class="token punctuation">.</span>MAX_VALUE<span class="token punctuation">;</span>shmin <span class="token operator">=</span> <span class="token class-name">Short</span><span class="token punctuation">.</span>MIN_VALUE<span class="token punctuation">;</span>imax <span class="token operator">=</span> <span class="token class-name">Integer</span><span class="token punctuation">.</span>MAX_VALUE<span class="token punctuation">;</span>imin <span class="token operator">=</span> <span class="token class-name">Integer</span><span class="token punctuation">.</span>MIN_VALUE<span class="token punctuation">;</span>lmax <span class="token operator">=</span> <span class="token class-name">Long</span><span class="token punctuation">.</span>MAX_VALUE<span class="token punctuation">;</span>lmin <span class="token operator">=</span> <span class="token class-name">Long</span><span class="token punctuation">.</span>MIN_VALUE<span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre>]]></content>
<categories>
<category> 小知识 </category>
</categories>
<tags>
<tag> 算法 </tag>
<tag> 小知识 </tag>
<tag> Java </tag>
</tags>
</entry>
<entry>
<title>二分算法模板</title>
<link href="/2024/05/07/er-fen-suan-fa-mo-ban/"/>
<url>/2024/05/07/er-fen-suan-fa-mo-ban/</url>
<content type="html"><![CDATA[<h2 id="一、整数二分"><a href="#一、整数二分" class="headerlink" title="一、整数二分"></a><strong>一、整数二分</strong></h2><p>二分的本质是<strong>查找边界</strong>，整数区间一分为二成两个区间，一部分满足性质1一部分满足性质2（如：左半边满足性质1，右半边满足性质2），那么既可以寻找性质1的边界，也可以寻找性质2的边界</p><p><strong>每次将区间缩小一半，选择答案所在的区间</strong></p><p><strong>二分的本质不是单调性。有单调性的题目可以二分，但是可以二分的题目不一定有单调性</strong></p><p>代码模板如下：</p><pre class="line-numbers language-c++" data-language="c++"><code class="language-c++">// 代码随想录写法，左闭右闭区间int search(int left,int right){ while (left <= right) { // 当left==right，区间[left, right]依然有效，所以用 <= int middle = left + ((right - left) / 2);// 防止溢出 等同于(left + right)/2 if (nums[middle] > target) { right = middle - 1; // target 在左区间，所以[left, middle - 1] } else if (nums[middle] < target) { left = middle + 1; // target 在右区间，所以[middle + 1, right] } else { // nums[middle] == target return middle; // 数组中找到目标值，直接返回下标 } }}<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>题目示例：1，2，2，3，3，5找出3的起始位置和终止位置</p><p>例题：<a href="https://leetcode.cn/problems/find-first-and-last-position-of-element-in-sorted-array/description/">34.在排序数组中查找元素的第一个和最后一个位置</a></p><h2 id="二、浮点数二分"><a href="#二、浮点数二分" class="headerlink" title="二、浮点数二分"></a><strong>二、浮点数二分</strong></h2><p>直接取mid判断落在哪个区间上，更新区间不断重复，直到精度足够为止(如：r - l < 1e-6)</p><pre class="line-numbers language-c++" data-language="c++"><code class="language-c++">bool check(double x){/* 检查x是否符合性质 */}double bsearch(double l, double r){ const double eps = 1e-6; while(r - l > eps){ // eps 表示精度，取决于题目对精度的要求 double mid = (l + r) / 2; // 不断二分 if(check(mid)){ r = mid; }else{ l = mid; } } return 1;}<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre>]]></content>
<categories>
<category> 算法 </category>
</categories>
<tags>
<tag> 二分算法 </tag>
<tag> 整数二分 </tag>
<tag> 浮点数二分 </tag>
</tags>
</entry>
<entry>
<title>【sysbench】OLTP基准测试使用</title>
<link href="/2024/04/19/sysbench-oltp-ji-zhun-ce-shi-shi-yong/"/>
<url>/2024/04/19/sysbench-oltp-ji-zhun-ce-shi-shi-yong/</url>
<content type="html"><![CDATA[<blockquote><p>MySQL版本：8.0.36</p><p>sysbench版本：1.0.20</p><p>操作的数据库名称：sysbench_test</p></blockquote><h2 id="1、创建sysbench-oltp测试的基础配置文件"><a href="#1、创建sysbench-oltp测试的基础配置文件" class="headerlink" title="1、创建sysbench oltp测试的基础配置文件"></a>1、创建sysbench oltp测试的基础配置文件</h2><p>一般使用sysbench测试MySQL性能的命令会很长，如以下命令：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">sysbench --threads<span class="token operator">=</span><span class="token number">16</span> --time<span class="token operator">=</span><span class="token number">60</span> --report-interval<span class="token operator">=</span><span class="token number">1</span> oltp_common.lua --mysql-host<span class="token operator">=</span>localhost --mysql-port<span class="token operator">=</span><span class="token number">3306</span> --mysql-user<span class="token operator">=</span>root --mysql-db<span class="token operator">=</span>sysbench_test --tables<span class="token operator">=</span><span class="token number">4</span> --table-size<span class="token operator">=</span><span class="token number">100000</span> prepare<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>需要指定很多参数。如果有配置文件的话可以简化操作。</p><p>创建基础配置文件my-sysbench.cnf，并写入一些内容（仅供参考）：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token assign-left variable">threads</span><span class="token operator">=</span><span class="token number">160</span><span class="token assign-left variable">time</span><span class="token operator">=</span><span class="token number">120</span>db-driver<span class="token operator">=</span>mysqlmysql-host<span class="token operator">=</span>localhostmysql-port<span class="token operator">=</span><span class="token number">3306</span>mysql-socket<span class="token operator">=</span>/home/czhang/mysql-8.0.36/mysql.sockmysql-user<span class="token operator">=</span>rootmysql-db<span class="token operator">=</span>sysbench_test<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>注意：在配置文件中不要指定 tables 等选项，因为这个参数时Lua脚本的参数，不是sysbench可执行文件的参数，所以该参数要在命令行中指定。</p><p>使用sysbench测试MySQL主要有三步：<br><strong>准备测试数据—>运行测试—>测试数据清理</strong></p><h2 id="2、准备测试数据"><a href="#2、准备测试数据" class="headerlink" title="2、准备测试数据"></a>2、准备测试数据</h2><p>我使用8张表，每张表包含10000条数据，表名使用默认值。命令执行目录是sysbench的Lua脚本所在目录。</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">sysbench --config-file<span class="token operator">=</span>/home/czhang/mysql-8.0.36/my-sysbench.cnf --tables<span class="token operator">=</span><span class="token number">8</span> --table-size<span class="token operator">=</span><span class="token number">10000</span> oltp_common.lua prepare<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>终端显示如下：<br><img src="/2024/04/19/sysbench-oltp-ji-zhun-ce-shi-shi-yong/prepare%E7%BB%93%E6%9E%9C%E6%98%BE%E7%A4%BA.png" alt="prepare结果显示"></p><h2 id="3、运行测试"><a href="#3、运行测试" class="headerlink" title="3、运行测试"></a>3、运行测试</h2><h3 id="1）oltp-read-write"><a href="#1）oltp-read-write" class="headerlink" title="1）oltp_read_write"></a>1）oltp_read_write</h3><p>建议先对支持 <code>prewarm</code> 选项的 Lua 脚本使用 <code>prewarm</code> 选项，以预热数据到内存，提高性能。</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">sysbench --config-file<span class="token operator">=</span>/home/czhang/mysql-8.0.36/my-sysbench.cnf --tables<span class="token operator">=</span><span class="token number">8</span> --table-size<span class="token operator">=</span><span class="token number">10000</span> oltp_read_write.lua prewarm<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>预热后再运行该脚本</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">sysbench --config-file<span class="token operator">=</span>/home/czhang/mysql-8.0.36/my-sysbench.cnf --tables<span class="token operator">=</span><span class="token number">8</span> --table-size<span class="token operator">=</span><span class="token number">10000</span> oltp_read_write.lua run<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><h3 id="2）oltp-point-select"><a href="#2）oltp-point-select" class="headerlink" title="2）oltp_point_select"></a>2）oltp_point_select</h3><pre class="line-numbers language-none"><code class="language-none">sysbench --config-file=/home/czhang/mysql-8.0.36/my-sysbench.cnf --tables=8 --table-size=10000 oltp_point_select.lua run<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><h3 id="3）oltp-write-only"><a href="#3）oltp-write-only" class="headerlink" title="3）oltp_write_only"></a>3）oltp_write_only</h3><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">sysbench --config-file<span class="token operator">=</span>/home/czhang/mysql-8.0.36/my-sysbench.cnf --tables<span class="token operator">=</span><span class="token number">8</span> --table-size<span class="token operator">=</span><span class="token number">10000</span> oltp_write_only.lua run<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><h3 id="4）oltp-read-only"><a href="#4）oltp-read-only" class="headerlink" title="4）oltp_read_only"></a>4）oltp_read_only</h3><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">sysbench --config-file<span class="token operator">=</span>/home/czhang/mysql-8.0.36/my-sysbench.cnf --tables<span class="token operator">=</span><span class="token number">8</span> --table-size<span class="token operator">=</span><span class="token number">10000</span> oltp_read_only.lua run<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>……</p><p>还有一些脚本没有运行，把命令行中的脚本名称替换即可。</p><h2 id="4、清理数据"><a href="#4、清理数据" class="headerlink" title="4、清理数据"></a>4、清理数据</h2><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">sysbench --config-file<span class="token operator">=</span>/home/czhang/mysql-8.0.36/my-sysbench.cnf --tables<span class="token operator">=</span><span class="token number">8</span> --table-size<span class="token operator">=</span><span class="token number">10000</span> oltp_common.lua cleanup<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p><strong>注意：</strong>清理数据时除了将prepare改成cleanup，其他全都得一样</p><h2 id="5、常用MySQL命令"><a href="#5、常用MySQL命令" class="headerlink" title="5、常用MySQL命令"></a>5、常用MySQL命令</h2><p>使用sysbench对MySQL进行基准测试时可能用得上的MySQL命令：</p><h3 id="5-1-查看指定数据库的容量大小"><a href="#5-1-查看指定数据库的容量大小" class="headerlink" title="5.1 查看指定数据库的容量大小"></a>5.1 查看指定数据库的容量大小</h3><pre class="line-numbers language-sql" data-language="sql"><code class="language-sql"><span class="token keyword">SELECT</span> <span class="token function">SUM</span><span class="token punctuation">(</span>data_length <span class="token operator">+</span> index_length<span class="token punctuation">)</span> <span class="token keyword">AS</span> total_size_bytes<span class="token punctuation">,</span>CONCAT<span class="token punctuation">(</span><span class="token function">ROUND</span><span class="token punctuation">(</span><span class="token function">SUM</span><span class="token punctuation">(</span>data_length <span class="token operator">+</span> index_length<span class="token punctuation">)</span> <span class="token operator">/</span> <span class="token number">1024</span> <span class="token operator">/</span> <span class="token number">1024</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token string">' MB'</span><span class="token punctuation">)</span> <span class="token keyword">AS</span> total_size_mb <span class="token keyword">FROM</span> information_schema<span class="token punctuation">.</span><span class="token keyword">TABLES</span> <span class="token keyword">WHERE</span> table_schema <span class="token operator">=</span> <span class="token string">'sysbench_test'</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>显示结果示例如下：<br><img src="/2024/04/19/sysbench-oltp-ji-zhun-ce-shi-shi-yong/Blog\source_posts\数据库容量大小.png"></p><h3 id="5-2-查看指定数据库中各表的大小"><a href="#5-2-查看指定数据库中各表的大小" class="headerlink" title="5.2 查看指定数据库中各表的大小"></a>5.2 查看指定数据库中各表的大小</h3><pre class="line-numbers language-sql" data-language="sql"><code class="language-sql"><span class="token keyword">SELECT</span> table_name<span class="token punctuation">,</span>data_length <span class="token operator">+</span> index_length <span class="token keyword">AS</span> size_bytes<span class="token punctuation">,</span>CONCAT<span class="token punctuation">(</span><span class="token function">ROUND</span><span class="token punctuation">(</span><span class="token punctuation">(</span>data_length <span class="token operator">+</span> index_length<span class="token punctuation">)</span> <span class="token operator">/</span> <span class="token number">1024</span> <span class="token operator">/</span> <span class="token number">1024</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token string">' MB'</span><span class="token punctuation">)</span> <span class="token keyword">AS</span> size_mb <span class="token keyword">FROM</span> information_schema<span class="token punctuation">.</span><span class="token keyword">TABLES</span> <span class="token keyword">WHERE</span> table_schema <span class="token operator">=</span> <span class="token string">'sysbench_test'</span> <span class="token keyword">ORDER</span> <span class="token keyword">BY</span> size_bytes <span class="token keyword">DESC</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>显示结果示例如下：</p><p><img src="/2024/04/19/sysbench-oltp-ji-zhun-ce-shi-shi-yong/%E6%95%B0%E6%8D%AE%E5%BA%93%E5%90%84%E8%A1%A8%E5%A4%A7%E5%B0%8F.png" alt="数据库各表大小"></p><h3 id="5-3-查看数据库各表中的记录数量"><a href="#5-3-查看数据库各表中的记录数量" class="headerlink" title="5.3 查看数据库各表中的记录数量"></a>5.3 查看数据库各表中的记录数量</h3><pre class="line-numbers language-sql" data-language="sql"><code class="language-sql"><span class="token keyword">SELECT</span> t1<span class="token punctuation">.</span>table_name<span class="token punctuation">,</span> <span class="token keyword">COALESCE</span><span class="token punctuation">(</span>t2<span class="token punctuation">.</span>row_count<span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">)</span> <span class="token keyword">AS</span> record_count<span class="token keyword">FROM</span> information_schema<span class="token punctuation">.</span><span class="token keyword">tables</span> t1<span class="token keyword">LEFT</span> <span class="token keyword">JOIN</span> <span class="token punctuation">(</span> <span class="token keyword">SELECT</span> table_name<span class="token punctuation">,</span> table_rows <span class="token keyword">AS</span> row_count <span class="token keyword">FROM</span> information_schema<span class="token punctuation">.</span><span class="token keyword">tables</span> <span class="token keyword">WHERE</span> table_schema <span class="token operator">=</span> <span class="token string">'sysbench_test'</span> <span class="token operator">AND</span> table_type <span class="token operator">=</span> <span class="token string">'BASE TABLE'</span><span class="token punctuation">)</span> t2 <span class="token keyword">ON</span> t1<span class="token punctuation">.</span>table_name <span class="token operator">=</span> t2<span class="token punctuation">.</span>table_name<span class="token keyword">WHERE</span> t1<span class="token punctuation">.</span>table_schema <span class="token operator">=</span> <span class="token string">'sysbench_test'</span> <span class="token operator">AND</span> t1<span class="token punctuation">.</span>table_type <span class="token operator">=</span> <span class="token string">'BASE TABLE'</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>显示结果示例如下：</p><p><img src="/2024/04/19/sysbench-oltp-ji-zhun-ce-shi-shi-yong/%E6%95%B0%E6%8D%AE%E5%BA%93%E5%90%84%E8%A1%A8%E8%AE%B0%E5%BD%95%E6%95%B0%E5%A4%A7%E5%B0%8F.png"></p><h2 id="6、常用cmd命令"><a href="#6、常用cmd命令" class="headerlink" title="6、常用cmd命令"></a>6、常用cmd命令</h2><p>显示包含“mysql”的进程</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token function">ps</span> -eo pid,psr,user,cmd <span class="token operator">|</span> <span class="token function">grep</span> mysql<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p><strong>Reference：</strong></p><p><a href="https://blog.csdn.net/wudi53433927/article/details/136946422">sysbench oltp测试示例</a></p>]]></content>
<categories>
<category> 工作负载 </category>
</categories>
<tags>
<tag> MySQL </tag>
<tag> 工作负载 </tag>
<tag> sysbench </tag>
<tag> 基准测试 </tag>
</tags>
</entry>
<entry>
<title>Linux普通用户无root权限安装MySQL 8.0.36</title>
<link href="/2024/04/17/linux-pu-tong-yong-hu-wu-root-quan-xian-an-zhuang-mysql-8-0-36/"/>
<url>/2024/04/17/linux-pu-tong-yong-hu-wu-root-quan-xian-an-zhuang-mysql-8-0-36/</url>
<content type="html"><![CDATA[<blockquote><p>Linux版本：Ubuntu 22.04 </p><p>MySQL版本：8.0.36</p><p>用户名：czhang</p><p>安装路径：/home/czhang/mysql-8.0.36</p></blockquote><h2 id="一、下载安装包"><a href="#一、下载安装包" class="headerlink" title="一、下载安装包"></a>一、下载安装包</h2><p>进入MySQL官网（<a href="https://dev.mysql.com/downloads/mysql/">MySQL下载官网</a> ）下载社区通用版 MySQL Community Server</p><p><img src="/2024/04/17/linux-pu-tong-yong-hu-wu-root-quan-xian-an-zhuang-mysql-8-0-36/MySQL%E5%AE%98%E7%BD%91%E6%88%AA%E5%9B%BE.png" alt="MySQL官网截图"></p><h2 id="二、解压并安装"><a href="#二、解压并安装" class="headerlink" title="二、解压并安装"></a>二、解压并安装</h2><h3 id="1、上传MySQL到服务器并解压："><a href="#1、上传MySQL到服务器并解压：" class="headerlink" title="1、上传MySQL到服务器并解压："></a>1、上传MySQL到服务器并解压：</h3><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">$ <span class="token function">tar</span> -xvf mysql-8.0.36-linux-glibc2.28-x86_64.tar.xz<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>将所有文件放在了 /home/czhang/mysql-8.0.36 路径下，文件名太长可以进行重命名</p><h3 id="2、创建编辑my-cnf配置文件（最初没有该文件）"><a href="#2、创建编辑my-cnf配置文件（最初没有该文件）" class="headerlink" title="2、创建编辑my.cnf配置文件（最初没有该文件）"></a>2、创建编辑my.cnf配置文件（最初没有该文件）</h3><p>在当前MySQL安装目录下，依次执行以下命令：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">$ <span class="token builtin class-name">cd</span> mysql-8.0.36$ <span class="token function">vim</span> my.cnf <span class="token comment">#编辑配置文件</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><h3 id="3、编辑my-cnf文件"><a href="#3、编辑my-cnf文件" class="headerlink" title="3、编辑my.cnf文件"></a>3、编辑my.cnf文件</h3><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token punctuation">[</span>client<span class="token punctuation">]</span><span class="token assign-left variable">port</span><span class="token operator">=</span><span class="token number">3306</span> <span class="token comment">#服务端口</span><span class="token assign-left variable">socket</span><span class="token operator">=</span>/home/czhang/mysql-8.0.36/mysql.sock <span class="token comment">#指定套接字文件</span><span class="token punctuation">[</span>mysqld<span class="token punctuation">]</span><span class="token comment"># skip-grant-tables #跳过root的密码验证</span><span class="token assign-left variable">port</span><span class="token operator">=</span><span class="token number">3306</span> <span class="token comment">#服务端口</span><span class="token assign-left variable">basedir</span><span class="token operator">=</span>/home/czhang/mysql-8.0.36 <span class="token comment">#mysql安装路径</span><span class="token assign-left variable">datadir</span><span class="token operator">=</span>/home/czhang/mysql-8.0.36/data <span class="token comment">#数据目录</span>pid-file<span class="token operator">=</span>/home/czhang/mysql-8.0.36/mysql.pid <span class="token comment">#指定pid文件</span><span class="token assign-left variable">socket</span><span class="token operator">=</span>/home/czhang/mysql-8.0.36/mysql.sock <span class="token comment">#指定套接字文件</span><span class="token assign-left variable">log_error</span><span class="token operator">=</span>/home/czhang/mysql-8.0.36/error.log <span class="token comment">#指定错误日志</span>server-id<span class="token operator">=</span><span class="token number">100</span> <span class="token comment">#Mysql主从唯一标识</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h3 id="4、安装启动MySQL"><a href="#4、安装启动MySQL" class="headerlink" title="4、安装启动MySQL"></a>4、安装启动MySQL</h3><h4 id="4-1-安装"><a href="#4-1-安装" class="headerlink" title="4.1 安装"></a>4.1 安装</h4><p>依次执行以下命令，指定配置文件安装并初始化mysql，没有报错即安装成功，返回了任何信息即为安装失败</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">$ <span class="token builtin class-name">cd</span> bin$ ./mysqld --defaults-file<span class="token operator">=</span>/home/czhang/mysql-8.0.36/my.cnf --initialize --user<span class="token operator">=</span>czhang --basedir<span class="token operator">=</span>/home/czhang/mysql-8.0.36 --datadir<span class="token operator">=</span>/home/czhang/mysql-8.0.36/data<span class="token comment">#安装并初始化mysql</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><h4 id="4-2-启动"><a href="#4-2-启动" class="headerlink" title="4.2 启动"></a>4.2 启动</h4><p>依次执行以下命令，没有报错并能成功监听3306端口即表示启动成功</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">$ ./mysqld_safe --defaults-file<span class="token operator">=</span>/home/czhang/mysql-8.0.36/my.cnf --user<span class="token operator">=</span>czhang <span class="token operator">&</span> <span class="token comment">#启动mysql</span>$ <span class="token function">netstat</span> -tln <span class="token operator">|</span> <span class="token function">grep</span> <span class="token number">3306</span> <span class="token comment">#查看是否成功监听3306端口</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><h2 id="四、登录MySQL"><a href="#四、登录MySQL" class="headerlink" title="四、登录MySQL"></a>四、登录MySQL</h2><h3 id="1、获取初始密码"><a href="#1、获取初始密码" class="headerlink" title="1、获取初始密码"></a>1、获取初始密码</h3><p>初始密码在安装根目录下的error.log文件中</p><h3 id="2、登录MySQL"><a href="#2、登录MySQL" class="headerlink" title="2、登录MySQL"></a>2、登录MySQL</h3><p>登录时需要指定mysql.sock文件启动，不然会报错。执行以下命令：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">$ ./mysql -u root -p -S /home/czhang/mysql-8.0.36/mysql.sock <span class="token comment">#指定sock文件登录</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><h3 id="3、修改密码"><a href="#3、修改密码" class="headerlink" title="3、修改密码"></a>3、修改密码</h3><p>成功登入mysql后，修改登录密码，执行以下sql语句：</p><pre class="line-numbers language-sql" data-language="sql"><code class="language-sql"><span class="token keyword">USE</span> mysql<span class="token punctuation">;</span><span class="token keyword">ALTER</span> <span class="token keyword">USER</span> <span class="token string">'root'</span><span class="token variable">@'localhost'</span> IDENTIFIED <span class="token keyword">BY</span> <span class="token string">'123456'</span><span class="token punctuation">;</span> <span class="token comment">--设置登录密码为123456</span>flush <span class="token keyword">privileges</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span></span></code></pre><h3 id="4、退出MySQL"><a href="#4、退出MySQL" class="headerlink" title="4、退出MySQL"></a>4、退出MySQL</h3><p>可以在终端中执行以下shell命令关闭MySQL：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">mysqladmin -u root <span class="token function">shutdown</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>或者在MySQL中执行SQL语句退出：</p><pre class="line-numbers language-sql" data-language="sql"><code class="language-sql"><span class="token keyword">SHUTDOWN</span><span class="token punctuation">;</span> <span class="token keyword">EXIT</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>至此，MySQL安装完成</p><h2 id="五、常用MySQL命令"><a href="#五、常用MySQL命令" class="headerlink" title="五、常用MySQL命令"></a>五、常用MySQL命令</h2><p>使用sysbench对MySQL进行基准测试时可能用得上的MySQL命令：</p><h3 id="1-查看指定数据库的容量大小"><a href="#1-查看指定数据库的容量大小" class="headerlink" title="1 查看指定数据库的容量大小"></a>1 查看指定数据库的容量大小</h3><pre class="line-numbers language-sql" data-language="sql"><code class="language-sql"><span class="token keyword">SELECT</span> <span class="token function">SUM</span><span class="token punctuation">(</span>data_length <span class="token operator">+</span> index_length<span class="token punctuation">)</span> <span class="token keyword">AS</span> total_size_bytes<span class="token punctuation">,</span>CONCAT<span class="token punctuation">(</span><span class="token function">ROUND</span><span class="token punctuation">(</span><span class="token function">SUM</span><span class="token punctuation">(</span>data_length <span class="token operator">+</span> index_length<span class="token punctuation">)</span> <span class="token operator">/</span> <span class="token number">1024</span> <span class="token operator">/</span> <span class="token number">1024</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token string">' MB'</span><span class="token punctuation">)</span> <span class="token keyword">AS</span> total_size_mb <span class="token keyword">FROM</span> information_schema<span class="token punctuation">.</span><span class="token keyword">TABLES</span> <span class="token keyword">WHERE</span> table_schema <span class="token operator">=</span> <span class="token string">'sysbench_test'</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>显示结果示例如下：<br><img src="/2024/04/17/linux-pu-tong-yong-hu-wu-root-quan-xian-an-zhuang-mysql-8-0-36/%E6%95%B0%E6%8D%AE%E5%BA%93%E5%AE%B9%E9%87%8F%E5%A4%A7%E5%B0%8F.png" alt="数据库容量大小"></p><h3 id="2-查看指定数据库中各表的大小"><a href="#2-查看指定数据库中各表的大小" class="headerlink" title="2 查看指定数据库中各表的大小"></a>2 查看指定数据库中各表的大小</h3><pre class="line-numbers language-sql" data-language="sql"><code class="language-sql"><span class="token keyword">SELECT</span> table_name<span class="token punctuation">,</span>data_length <span class="token operator">+</span> index_length <span class="token keyword">AS</span> size_bytes<span class="token punctuation">,</span>CONCAT<span class="token punctuation">(</span><span class="token function">ROUND</span><span class="token punctuation">(</span><span class="token punctuation">(</span>data_length <span class="token operator">+</span> index_length<span class="token punctuation">)</span> <span class="token operator">/</span> <span class="token number">1024</span> <span class="token operator">/</span> <span class="token number">1024</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token string">' MB'</span><span class="token punctuation">)</span> <span class="token keyword">AS</span> size_mb <span class="token keyword">FROM</span> information_schema<span class="token punctuation">.</span><span class="token keyword">TABLES</span> <span class="token keyword">WHERE</span> table_schema <span class="token operator">=</span> <span class="token string">'sysbench_test'</span> <span class="token keyword">ORDER</span> <span class="token keyword">BY</span> size_bytes <span class="token keyword">DESC</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>显示结果示例如下：</p><p><img src="/2024/04/17/linux-pu-tong-yong-hu-wu-root-quan-xian-an-zhuang-mysql-8-0-36/%E6%95%B0%E6%8D%AE%E5%BA%93%E5%90%84%E8%A1%A8%E5%A4%A7%E5%B0%8F.png" alt="数据库各表大小"></p><h3 id="3-查看数据库各表中的记录数量"><a href="#3-查看数据库各表中的记录数量" class="headerlink" title="3 查看数据库各表中的记录数量"></a>3 查看数据库各表中的记录数量</h3><pre class="line-numbers language-sql" data-language="sql"><code class="language-sql"><span class="token keyword">SELECT</span> t1<span class="token punctuation">.</span>table_name<span class="token punctuation">,</span> <span class="token keyword">COALESCE</span><span class="token punctuation">(</span>t2<span class="token punctuation">.</span>row_count<span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">)</span> <span class="token keyword">AS</span> record_count<span class="token keyword">FROM</span> information_schema<span class="token punctuation">.</span><span class="token keyword">tables</span> t1<span class="token keyword">LEFT</span> <span class="token keyword">JOIN</span> <span class="token punctuation">(</span> <span class="token keyword">SELECT</span> table_name<span class="token punctuation">,</span> table_rows <span class="token keyword">AS</span> row_count <span class="token keyword">FROM</span> information_schema<span class="token punctuation">.</span><span class="token keyword">tables</span> <span class="token keyword">WHERE</span> table_schema <span class="token operator">=</span> <span class="token string">'sysbench_test'</span> <span class="token operator">AND</span> table_type <span class="token operator">=</span> <span class="token string">'BASE TABLE'</span><span class="token punctuation">)</span> t2 <span class="token keyword">ON</span> t1<span class="token punctuation">.</span>table_name <span class="token operator">=</span> t2<span class="token punctuation">.</span>table_name<span class="token keyword">WHERE</span> t1<span class="token punctuation">.</span>table_schema <span class="token operator">=</span> <span class="token string">'sysbench_test'</span> <span class="token operator">AND</span> t1<span class="token punctuation">.</span>table_type <span class="token operator">=</span> <span class="token string">'BASE TABLE'</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>显示结果示例如下：</p><p><img src="/2024/04/17/linux-pu-tong-yong-hu-wu-root-quan-xian-an-zhuang-mysql-8-0-36/%E6%95%B0%E6%8D%AE%E5%BA%93%E5%90%84%E8%A1%A8%E8%AE%B0%E5%BD%95%E6%95%B0%E5%A4%A7%E5%B0%8F.png" alt="数据库各表记录数大小"></p><h2 id="六、常用cmd命令"><a href="#六、常用cmd命令" class="headerlink" title="六、常用cmd命令"></a>六、常用cmd命令</h2><p>显示包含“mysql”的进程</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token function">ps</span> -eo pid,psr,user,cmd <span class="token operator">|</span> <span class="token function">grep</span> mysql<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p><strong>Reference</strong>：</p><p><a href="https://www.cnblogs.com/chenkx6/p/13366638.html">1</a></p><p><a href="https://cloud.tencent.com/developer/article/1583129">2</a></p><p><a href="https://blog.csdn.net/suixinfeixiangfei/article/details/121323984">3</a></p><p><a href="https://blog.csdn.net/Shadownow/article/details/115311933">4</a></p>]]></content>
<categories>
<category> 工作负载 </category>
</categories>
<tags>
<tag> MySQL </tag>
<tag> 工作负载 </tag>
<tag> 环境搭建 </tag>
</tags>
</entry>
<entry>
<title>NEMO海洋模型的安装、搭建与运行</title>
<link href="/2024/04/02/nemo-hai-yang-mo-xing-de-an-zhuang-da-jian-yu-yun-xing/"/>
<url>/2024/04/02/nemo-hai-yang-mo-xing-de-an-zhuang-da-jian-yu-yun-xing/</url>
<content type="html"><![CDATA[<p>笔者在安装构建NEMO（<strong>N</strong>ucleus for<strong>E</strong>uropean<strong>M</strong>odelling of the<strong>O</strong>cean）的时候苦于资料太少，花费了不少时间和精力，踩了不少坑。因此笔者将安装过程进行总结，以供大家参考。</p><h2 id="1-系统信息"><a href="#1-系统信息" class="headerlink" title="1. 系统信息"></a>1. 系统信息</h2><p>OS信息：Linux black 5.15.0-89-generic #99-Ubuntu x86_64 GNU/Linux</p><p>安装路径：软件安装包放在： /home/czhang/softwarepkg</p><p>相关依赖软件安装在：/home/czhang/local</p><p>NEMO安装在：/home/czhang/NEMO</p><p>XIOS安装在：/home/czhang/xios</p><blockquote><p>各软件安装版本如下：<br>curl-7.81.0<br>hdf5-1.14.3<br>mpich-4.2.0<br>netcdf-c-4.7.4<br>netcdf-fortran-4.5.3<br>pnetcdf-1.12.3<br>szip-2.1.1<br>zlib-1.2.11</p></blockquote><h2 id="2-安装MPICH"><a href="#2-安装MPICH" class="headerlink" title="2. 安装MPICH"></a>2. 安装MPICH</h2><p>在/home/czhang/local下创建mpich文件夹</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">$ <span class="token function">tar</span> -zxvf mpich-4.2.0.tar.gz$ <span class="token builtin class-name">cd</span> mpich-4.2.0$ ./configure --prefix<span class="token operator">=</span>/home/czhang/local/mpich$ <span class="token function">make</span>$ <span class="token function">make</span> <span class="token function">install</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>安装后需要将mpich的相应路径添加到环境变量当中。</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token builtin class-name">export</span> <span class="token assign-left variable">LD_LIBRARY_PATH</span><span class="token operator">=</span>/home/czhang/local/mpich/lib<span class="token builtin class-name">export</span> <span class="token assign-left variable"><span class="token environment constant">PATH</span></span><span class="token operator">=</span><span class="token environment constant">$PATH</span>:/home/czhang/local/mpich/bin<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><p>也可以在.bashrc中，添加随后 source ~/.bashrc</p><h2 id="3-安装NetCDF"><a href="#3-安装NetCDF" class="headerlink" title="3. 安装NetCDF"></a>3. 安装NetCDF</h2><p>在/home/czhang/local下创建netcdf文件夹。安装的每一个依赖软件均需在其源代码目录下进行</p><h3 id="1-安装zlib"><a href="#1-安装zlib" class="headerlink" title="(1)安装zlib"></a>(1)安装zlib</h3><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">$ <span class="token function">tar</span> -zxvf zlib-1.2.11.tar.gz$ <span class="token builtin class-name">cd</span> zlib-1.2.11$ ./configure --prefix<span class="token operator">=</span>/home/czhang/local/netcdf$ <span class="token function">make</span>$ <span class="token function">make</span> <span class="token function">install</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span></span></code></pre><h3 id="2-安装szip"><a href="#2-安装szip" class="headerlink" title="(2)安装szip"></a>(2)安装szip</h3><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">$ <span class="token function">tar</span> -zxvf szip-2.1.1.tar.gz$ <span class="token builtin class-name">cd</span> szip-2.1.1$ ./configure --prefix<span class="token operator">=</span>/home/czhang/local/netcdf$ <span class="token function">make</span>$ <span class="token function">make</span> <span class="token function">install</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span></span></code></pre><h3 id="3-安装curl"><a href="#3-安装curl" class="headerlink" title="(3)安装curl"></a>(3)安装curl</h3><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">$ <span class="token function">tar</span> -zxvf curl-7.81.0.tar.gz$ <span class="token builtin class-name">cd</span> curl-7.81.0$ ./configure --prefix<span class="token operator">=</span>/home/czhang/local/netcdf -with-openssl <span class="token comment"># 这里要看自己系统上用的什么ssl</span>$ <span class="token function">make</span>$ <span class="token function">make</span> <span class="token function">install</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span></span></code></pre><h3 id="4-安装HDF5"><a href="#4-安装HDF5" class="headerlink" title="(4)安装HDF5"></a>(4)安装HDF5</h3><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">$ <span class="token function">tar</span> -zxvf hdf5-1.14.3.tar.gz$ <span class="token builtin class-name">cd</span> hdf5-1.14.3$ <span class="token builtin class-name">export</span> <span class="token assign-left variable">CPPFLAGS</span><span class="token operator">=</span>-I /home/czhang/local/netcdf/include$ <span class="token builtin class-name">export</span> <span class="token assign-left variable">LDFLAGS</span><span class="token operator">=</span>-L /home/czhang/local/netcdf/lib$ <span class="token builtin class-name">export</span> <span class="token assign-left variable">LD_LIBRARY_PATH</span><span class="token operator">=</span>/home/czhang/local/netcdf/lib$ ./configure --prefix<span class="token operator">=</span>/home/czhang/local/netcdf --enable-parallel --enable-fortran$ <span class="token function">make</span>$ <span class="token function">make</span> <span class="token function">install</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><h3 id="5-安装PNetCDF"><a href="#5-安装PNetCDF" class="headerlink" title="(5)安装PNetCDF"></a>(5)安装PNetCDF</h3><p>在/home/czhang/local下创建pnetcdf文件夹，pnetcdf安装在该文件夹中</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">$ <span class="token function">tar</span> -zxvf pnetcdf-1.12.3.tar.gz$ <span class="token builtin class-name">cd</span> pnetcdf-1.12.3$ ./configure --prefix<span class="token operator">=</span>/home/czhang/local/pnetcdf --enable-fortran --enable-large-file-test --enable-shared$ <span class="token function">make</span>$ <span class="token function">make</span> <span class="token function">install</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span></span></code></pre><h3 id="6-安装NetCDF-C"><a href="#6-安装NetCDF-C" class="headerlink" title="(6)安装NetCDF-C"></a>(6)安装NetCDF-C</h3><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">$ <span class="token function">tar</span> -zxvf netcdf-c-4.7.4.tar.gz$ <span class="token builtin class-name">cd</span> netcdf-c-4.7.4$ ./configure --prefix<span class="token operator">=</span>/home/czhang/local/netcdf --enable-pnetcdf --enable-large-file-tests --enable-largefile --enable-parallel-tests --enable-shared --with-pic --disable-doxygen --enable-netcdf-4 $ <span class="token function">make</span>$ <span class="token function">make</span> <span class="token function">install</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>成功后会有 congratulations</p><h3 id="7-安装NetCDF-Fortran"><a href="#7-安装NetCDF-Fortran" class="headerlink" title="(7)安装NetCDF-Fortran"></a>(7)安装NetCDF-Fortran</h3><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">$ <span class="token function">tar</span> -zxvf netcdf-fortran-4.5.3.tar.gz <span class="token comment"># 注意：该版本需要netcdf-c在4.7.4及以上</span>$ <span class="token builtin class-name">cd</span> netcdf-fortran-4.5.3$ <span class="token builtin class-name">export</span> <span class="token assign-left variable">LIBS</span><span class="token operator">=</span>-lnetcdf$ ./configure --prefix<span class="token operator">=</span>/home/czhang/local/netcdf --disable-static --enable-shared --with-pic --enable-parallel-tests --enable-large-file-tests --enable-largefile $ <span class="token function">make</span>$ <span class="token function">make</span> <span class="token function">install</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>成功后会有 congratulations</p><p><strong>安装完成后需要配置环境变量</strong>，笔者在 .bashrc 文件添加的内容如下：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token builtin class-name">export</span> <span class="token assign-left variable">DIR</span><span class="token operator">=</span>/home/czhang/local<span class="token builtin class-name">export</span> <span class="token assign-left variable">NETCDF</span><span class="token operator">=</span><span class="token variable">$DIR</span>/netcdf<span class="token builtin class-name">export</span> <span class="token assign-left variable">MPI</span><span class="token operator">=</span><span class="token variable">$DIR</span>/mpich<span class="token builtin class-name">export</span> <span class="token assign-left variable">PNETCDF</span><span class="token operator">=</span><span class="token variable">$DIR</span>/pnetcdf<span class="token builtin class-name">export</span> <span class="token assign-left variable">CPPFLAGS</span><span class="token operator">=</span><span class="token string">"-I<span class="token variable">$MPI</span>/include -I<span class="token variable">$NETCDF</span>/include -I<span class="token variable">$PNETCDF</span>/include"</span><span class="token builtin class-name">export</span> <span class="token assign-left variable">LDFLAGS</span><span class="token operator">=</span><span class="token string">"<span class="token variable">$LDFLAGS</span> -L<span class="token variable">$NETCDF</span>/lib -L<span class="token variable">$MPI</span>/lib -L<span class="token variable">$PNETCDF</span>/lib -I<span class="token variable">$NETCDF</span>/include"</span><span class="token builtin class-name">export</span> <span class="token assign-left variable">FCFLAGS</span><span class="token operator">=</span><span class="token string">"-fallow-argument-mismatch"</span><span class="token builtin class-name">export</span> <span class="token assign-left variable">FFLAGS</span><span class="token operator">=</span><span class="token string">"-I<span class="token variable">$MPI</span>/include -L<span class="token variable">$MPI</span>/lib -I<span class="token variable">$NETCDF</span>/include -fallow-argument-mismatch"</span><span class="token builtin class-name">export</span> <span class="token assign-left variable">NCDF_F_HOME</span><span class="token operator">=</span><span class="token variable">$NETCDF</span><span class="token builtin class-name">export</span> <span class="token assign-left variable">NCDF_C_HOME</span><span class="token operator">=</span><span class="token variable">$NETCDF</span><span class="token builtin class-name">export</span> <span class="token assign-left variable">HDF5_HOME</span><span class="token operator">=</span><span class="token variable">$NETCDF</span><span class="token builtin class-name">export</span> <span class="token assign-left variable">LD_LIBRARY_PATH</span><span class="token operator">=</span><span class="token variable">$MPI</span>/lib:<span class="token variable">$NETCDF</span>/lib:<span class="token variable">$PNETCDF</span>/lib:<span class="token variable">$LD_LIBRARY_PATH</span><span class="token builtin class-name">export</span> <span class="token assign-left variable"><span class="token environment constant">PATH</span></span><span class="token operator">=</span><span class="token environment constant">$PATH</span><span class="token builtin class-name">:</span><span class="token variable">$MPI</span>/bin:<span class="token variable">$NETCDF</span>/bin:<span class="token variable">$NETCDF</span>/include<span class="token builtin class-name">export</span> <span class="token assign-left variable">CC</span><span class="token operator">=</span>mpicc <span class="token comment">#gcc</span><span class="token builtin class-name">export</span> <span class="token assign-left variable">CXX</span><span class="token operator">=</span>mpicxx <span class="token comment">#g++</span><span class="token builtin class-name">export</span> <span class="token assign-left variable">FC</span><span class="token operator">=</span>mpif90 <span class="token comment">#gfortran</span><span class="token builtin class-name">export</span> <span class="token assign-left variable">FCFLAGS</span><span class="token operator">=</span><span class="token string">"-m64 <span class="token variable">$FCFLAGS</span>"</span> <span class="token builtin class-name">export</span> <span class="token assign-left variable">F77</span><span class="token operator">=</span>mpif77 <span class="token comment">#gfortran</span><span class="token builtin class-name">export</span> <span class="token assign-left variable">FFLAGS</span><span class="token operator">=</span><span class="token string">"-m64 <span class="token variable">$FFLAGS</span>"</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>配置好了之后，检查一下版本和路径</p><h2 id="4-安装XIOS"><a href="#4-安装XIOS" class="headerlink" title="4. 安装XIOS"></a>4. 安装XIOS</h2><p>提取并解析XIOS源代码，并将安装文件夹命名为xios。</p><pre class="line-numbers language-text" data-language="text"><code class="language-text">svn co http://forge.ipsl.jussieu.fr/ioserver/svn/XIOS2/trunk xios<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>在 xios/arch 目录下找到相应的架构配置文件并修改。笔者这里是用的GCC_LINUX，需要修改 .path, .env, .fcm 文件。</p><pre class="line-numbers language-text" data-language="text"><code class="language-text"># arch-GCC_LINUX.envexport HDF5_INC_DIR=$HOME/local/netcdf/include #根据自己情况修改export HDF5_LIB_DIR=$HOME/local/netcdf/lib #根据自己情况修改export NETCDF_INC_DIR=$HOME/local/netcdf/include #根据自己情况修改export NETCDF_LIB_DIR=$HOME/local/netcdf/lib #根据自己情况修改export BOOST_INC_DIR=$HOME/boostexport BOOST_LIB_DIR=$HOME/boost<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>具体路径需要根据自己的安装路径做相应修改。</p><pre class="line-numbers language-text" data-language="text"><code class="language-text"># arch-GCC_LINUX.fcm################################################################################################### Projet XIOS ###################################################################################################%CCOMPILER /home/czhang/local/mpich/bin/mpicc #根据自己情况修改%FCOMPILER /home/czhang/local/mpich/bin/mpif90 #根据自己情况修改%LINKER /home/czhang/local/mpich/bin/mpif90 #根据自己情况修改%BASE_CFLAGS -w -std=c++11 -D__XIOS_EXCEPTION -D_GLIBCXX_USE_CXX11_ABI=0 -ffree-line-length-none #这个标志需要在原基础上添加一些东西%PROD_CFLAGS -O3 -DBOOST_DISABLE_ASSERTS%DEV_CFLAGS -g -O2%DEBUG_CFLAGS -g%BASE_FFLAGS -D__NONE__%PROD_FFLAGS -O3%DEV_FFLAGS -g -O2%DEBUG_FFLAGS -g%BASE_INC -D__NONE__%BASE_LD -lstdc++%CPP cpp%FPP cpp -P%MAKE make<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>具体路径需要根据自己的安装路径做相应修改，FLAGS按照上述修改即可。</p><pre class="line-numbers language-text" data-language="text"><code class="language-text"># arch-GCC_LINUX.pathNETCDF_INCDIR="-I $NETCDF_INC_DIR"NETCDF_LIBDIR="-L $NETCDF_LIB_DIR"NETCDF_LIB="-lnetcdff -lnetcdf"MPI_INCDIR=""MPI_LIBDIR=""MPI_LIB=""HDF5_INCDIR="-I $HDF5_INC_DIR"HDF5_LIBDIR="-L $HDF5_LIB_DIR"HDF5_LIB="-lhdf5_hl -lhdf5 -lhdf5 -lz"<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>以上只展示到了 HDF5 的设置，后面的不用改变。去除 lcurl 标志即可。</p><p>配置完成后就可以在xios源代码目录下进行编译了。输入命令：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">./make_xios --full --arch GCC_LINUX -j <span class="token number">160</span> <span class="token operator">|&</span> <span class="token function">tee</span> compile_log.txt<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>选用GCC_LINUX架构配置进行编译。-j 表示使用多少个线程进行编译，tee compile_log.txt 表示将编译产生的信息存储在txt文件中，这是为了出问题时方便查看。</p><p>XIOS编译的时间很长，同时编译完成后不会有成功或恭喜信息，看到 finished 并且没有 error 报错就说明完成了。</p><h2 id="5-安装并编译NEMO"><a href="#5-安装并编译NEMO" class="headerlink" title="5. 安装并编译NEMO"></a>5. 安装并编译NEMO</h2><p>创建NEMO文件夹，并将压缩包解压。编译NEMO之前同样需要修改架构配置文件。笔者这里使用的是linux_gfortran架构</p><p>在arch文件夹下找到 arch-linux_gfortran.fcm文件并修改</p><pre class="line-numbers language-text" data-language="text"><code class="language-text">%NCDF_HOME /home/czhang/local/netcdf%HDF5_HOME /home/czhang/local/netcdf%NCDF_C_HOME /home/czhang/local/netcdf%NCDF_F_HOME /home/czhang/local/netcdf%XIOS_HOME /home/czhang/xios%NCDF_INC -I%NCDF_F_HOME/include -I%NCDF_C_HOME/include -I%HDF5_HOME/include%NCDF_LIB -L%NCDF_F_HOME/lib -lnetcdff -L%NCDF_C_HOME/lib -lnetcdf -lstdc++%XIOS_INC -I%XIOS_HOME/inc%XIOS_LIB -L%XIOS_HOME/lib -lxios -lstdc++%OASIS_INC -I%OASIS_HOME/build/lib/mct -I%OASIS_HOME/build/lib/psmile.MPI1%OASIS_LIB -L%OASIS_HOME/lib -lpsmile.MPI1 -lmct -lmpeu -lscrip%CPP cpp -Dkey_nosignedzero%FC mpif90 -c -cpp%FCFLAGS -I/home/czhang/local/netcdf/include $(FCFLAGS) -fdefault-real-8 -O3 -funroll-all-loops -fcray-pointer -ffree-line-length-none -fallow-argument-mismatch -cpp%FFLAGS %FCFLAGS%LD mpif90%LDFLAGS%FPPFLAGS -P -C -traditional%AR ar%ARFLAGS rs%MK make%USER_INC %XIOS_INC %NCDF_INC%USER_LIB %XIOS_LIB %NCDF_LIB%CC cc%CFLAGS -O0<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>在该配置文件中需要指明netcdf，hdf5，xios的路径</p><p>之后就可以进行NEMO 的编译。在源代码根目录进行：</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">./makenemo -m linux_gfortran -r GYRE_PISCES -n test1<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>之后就可以在cfgs文件夹下看到test1文件夹，其中包含 BLD, EXP00, MY_SRC, WORK, cpp_test1.fcm，在EXP00文件夹下有nemo执行程序</p><h2 id="6-运行NEMO"><a href="#6-运行NEMO" class="headerlink" title="6. 运行NEMO"></a>6. 运行NEMO</h2><p>在EXP00文件夹下，有一些初始化的输入文件（namelist，用于输入的*.xml文件等），如果需要使用其他输入文件需要将他们放在这个文件夹中</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">$ <span class="token builtin class-name">cd</span> cfgs/test1/EXP00/ <span class="token comment"># 进入EXP00文件夹中</span>$ mpirun -n <span class="token variable">$NPROCS</span> ./nemo <span class="token comment"># $NPROCS 是指要运行的线程数 ， mpirun是自己系统的MPI的封装接口</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><h2 id="7-对于NEMO的一些配置"><a href="#7-对于NEMO的一些配置" class="headerlink" title="7. 对于NEMO的一些配置"></a>7. 对于NEMO的一些配置</h2><h3 id="7-1-更改输入输出文件路径"><a href="#7-1-更改输入输出文件路径" class="headerlink" title="7.1 更改输入输出文件路径"></a>7.1 更改输入输出文件路径</h3><p>在<strong>namelist_ref</strong>文件中</p><pre class="line-numbers language-fortran" data-language="fortran"><code class="language-fortran">cn_ocerst_indir <span class="token operator">=</span> <span class="token string">"./input"</span> <span class="token comment">! directory from which to read input ocean restarts</span>cn_ocerst_outdir <span class="token operator">=</span> <span class="token string">"./output_ocean_restart"</span> <span class="token comment">! directory in which to write output ocean restarts</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><p>在<strong>namelist_top_ref</strong>文件中</p><pre class="line-numbers language-fortran" data-language="fortran"><code class="language-fortran">cn_trcrst_outdir <span class="token operator">=</span> <span class="token string">"./output_restart_trcrst"</span> <span class="token comment">! directory to which to write output passive tracer restarts</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>在<strong>file_def_nemo.xml</strong>文件中</p><pre class="line-numbers language-markup" data-language="markup"><code class="language-markup"><span class="token tag"><span class="token tag"><span class="token punctuation"><</span>file_definition</span> <span class="token attr-name">type</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>multiple_file<span class="token punctuation">"</span></span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>output_time/@expname@_@freq@_@startdate@_@enddate@<span class="token punctuation">"</span></span> <span class="token attr-name">sync_freq</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>1mo<span class="token punctuation">"</span></span> <span class="token attr-name">min_digits</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>4<span class="token punctuation">"</span></span><span class="token punctuation">></span></span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>mesh_mask文件 和 ocean_output文件无法更改输出目录，除非修改NEMO源代码</p><h3 id="7-2-部分参数的作用"><a href="#7-2-部分参数的作用" class="headerlink" title="7.2 部分参数的作用"></a>7.2 部分参数的作用</h3><pre class="line-numbers language-fortran" data-language="fortran"><code class="language-fortran"><span class="token comment">! 在namelist_cfg文件中，调整分辨率</span><span class="token comment">! jpiglo, jpjglo参数不应该出现在该文件中，不用调整</span>nn_GYRE <span class="token operator">=</span> <span class="token number">25</span> <span class="token comment">! GYRE resolution [1/degrees] 。分辨率（度）的倒数</span>ln_bench <span class="token operator">=</span> <span class="token boolean">.true.</span> <span class="token comment">! ! =T benchmark with gyre: the gridsize is kept constant。将NEMO用于作为Benchmark</span>jpkglo <span class="token operator">=</span> <span class="token number">31</span> <span class="token comment">! number of model levels。模拟时的模型层数或深度</span>rn_Dt <span class="token operator">=</span> <span class="token number">7200.</span> <span class="token comment">! time step for the dynamics。设置模拟的时间步长</span><span class="token comment">! 在namelist_ref文件中，调整用于MPI并行计算的网格点，将两个参数设置为0使得系统自动调整网格</span>jpni <span class="token operator">=</span> <span class="token number">0</span> <span class="token comment">! number of processors following i (set automatically if < 1), see also ln_listonly = T</span>jpnj <span class="token operator">=</span> <span class="token number">0</span> <span class="token comment">! number of processors following j (set automatically if < 1), see also ln_listonly = T</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>模型运行的信息在 ocean.output 文件中，通过该文件展示的信息来判断应该用多少MPI进程</p><p><strong>References:</strong></p>]]></content>
<categories>
<category> 工作负载 </category>
</categories>
<tags>
<tag> 工作负载 </tag>
<tag> 环境搭建 </tag>
<tag> HPC </tag>
<tag> 分布式 </tag>
</tags>
</entry>
<entry>
<title>IntelliJ IDEA 常用快捷键一览表</title>
<link href="/2024/04/02/intellij-idea-chang-yong-kuai-jie-jian-yi-lan-biao/"/>
<url>/2024/04/02/intellij-idea-chang-yong-kuai-jie-jian-yi-lan-biao/</url>
<content type="html"><![CDATA[<h2 id="1-IDEA的日常快捷键"><a href="#1-IDEA的日常快捷键" class="headerlink" title="1-IDEA的日常快捷键"></a><strong>1-IDEA的日常快捷键</strong></h2><h3 id="第1组：通用型"><a href="#第1组：通用型" class="headerlink" title="第1组：通用型"></a><strong>第1组：通用型</strong></h3><table><thead><tr><th>说明</th><th>快捷键</th></tr></thead><tbody><tr><td>复制代码-copy</td><td>ctrl + c</td></tr><tr><td>粘贴-paste</td><td>ctrl + v</td></tr><tr><td>剪切-cut</td><td>ctrl + x</td></tr><tr><td>撤销-undo</td><td>ctrl + z</td></tr><tr><td>反撤销-redo</td><td>ctrl + shift + z</td></tr><tr><td>保存-save all</td><td>ctrl + s</td></tr><tr><td>全选-select all</td><td>ctrl + a</td></tr></tbody></table><h3 id="第2组：提高编写速度（上）"><a href="#第2组：提高编写速度（上）" class="headerlink" title="第2组：提高编写速度（上）"></a><strong>第2组：提高编写速度（上）</strong></h3><table><thead><tr><th>说明</th><th>快捷键</th></tr></thead><tbody><tr><td>智能提示-edit</td><td>alt + enter</td></tr><tr><td>提示代码模板-insert live template</td><td>ctrl+j</td></tr><tr><td>使用xx块环绕-surround with …</td><td>ctrl+alt+t</td></tr><tr><td>调出生成getter/setter/构造器等结构-generate …</td><td>alt+insert</td></tr><tr><td>自动生成返回值变量-introduce variable …</td><td>ctrl+alt+v</td></tr><tr><td>复制指定行的代码-duplicate line or selection</td><td>ctrl+d</td></tr><tr><td>删除指定行的代码-delete line</td><td>ctrl+y</td></tr><tr><td>切换到下一行代码空位-start new line</td><td>shift + enter</td></tr><tr><td>切换到上一行代码空位-start new line before current</td><td>ctrl +alt+ enter</td></tr><tr><td>向上移动代码-move statement up</td><td>ctrl+shift+↑</td></tr><tr><td>向下移动代码-move statement down</td><td>ctrl+shift+↓</td></tr><tr><td>向上移动一行-move line up</td><td>alt+shift+↑</td></tr><tr><td>向下移动一行-move line down</td><td>alt+shift+↓</td></tr><tr><td>方法的形参列表提醒-parameter info</td><td>ctrl+p</td></tr></tbody></table><h3 id="第3组：提高编写速度（下）"><a href="#第3组：提高编写速度（下）" class="headerlink" title="第3组：提高编写速度（下）"></a><strong>第3组：提高编写速度（下）</strong></h3><table><thead><tr><th>说明</th><th>快捷键</th></tr></thead><tbody><tr><td>批量修改指定的变量名、方法名、类名等-rename</td><td>shift+f6</td></tr><tr><td>抽取代码重构方法-extract method …</td><td>ctrl+alt+m</td></tr><tr><td>重写父类的方法-override methods …</td><td>ctrl+o</td></tr><tr><td>实现接口的方法-implements methods …</td><td>ctrl+i</td></tr><tr><td>选中的结构的大小写的切换-toggle case</td><td>ctrl+shift+u</td></tr><tr><td>批量导包-optimize imports</td><td>ctrl+alt+o</td></tr></tbody></table><h3 id="第4组：类结构、查找和查看源码"><a href="#第4组：类结构、查找和查看源码" class="headerlink" title="第4组：类结构、查找和查看源码"></a><strong>第4组：类结构、查找和查看源码</strong></h3><table><thead><tr><th>说明</th><th>快捷键</th></tr></thead><tbody><tr><td>如何查看源码-go to class…</td><td>ctrl + 选中指定的结构 或 ctrl+n</td></tr><tr><td>显示当前类结构，支持搜索指定的方法、属性等-file structure</td><td>ctrl+f12</td></tr><tr><td>退回到前一个编辑的页面-back</td><td>ctrl+alt+←</td></tr><tr><td>进入到下一个编辑的页面-forward</td><td>ctrl+alt+→</td></tr><tr><td>打开的类文件之间切换-select previous/next tab</td><td>alt+←/→</td></tr><tr><td>光标选中指定的类，查看继承树结构-Type Hierarchy</td><td>ctrl+h</td></tr><tr><td>查看方法文档-quick documentation</td><td>ctrl+q</td></tr><tr><td>类的UML关系图-show uml popup</td><td>ctrl+alt+u</td></tr><tr><td>定位某行-go to line/column</td><td>ctrl+g</td></tr><tr><td>回溯变量或方法的来源-go to implementation(s)</td><td>ctrl+alt+b</td></tr><tr><td>折叠方法实现-collapse all</td><td>ctrl+shift+ -</td></tr><tr><td>展开方法实现-expand all</td><td>ctrl+shift+ +</td></tr></tbody></table><h3 id="第5组：查找、替换与关闭"><a href="#第5组：查找、替换与关闭" class="headerlink" title="第5组：查找、替换与关闭"></a><strong>第5组：查找、替换与关闭</strong></h3><table><thead><tr><th>说明</th><th>快捷键</th></tr></thead><tbody><tr><td>查找指定的结构</td><td>ctlr+f</td></tr><tr><td>快速查找：选中的Word快速定位到下一个-find next</td><td>ctrl+l</td></tr><tr><td>查找与替换-replace</td><td>ctrl+r</td></tr><tr><td>直接定位到当前行的首位-move caret to line start</td><td>home</td></tr><tr><td>直接定位到当前行的末位 -move caret to line end</td><td>end</td></tr><tr><td>查询当前元素在当前文件中的引用，然后按 F3 可以选择</td><td>ctrl+f7</td></tr><tr><td>全项目搜索文本-find in path …</td><td>ctrl+shift+f</td></tr><tr><td>关闭当前窗口-close</td><td>ctrl+f4</td></tr></tbody></table><h3 id="第6组：调整格式"><a href="#第6组：调整格式" class="headerlink" title="第6组：调整格式"></a><strong>第6组：调整格式</strong></h3><table><thead><tr><th>说明</th><th>快捷键</th></tr></thead><tbody><tr><td>格式化代码-reformat code</td><td>ctrl+alt+l</td></tr><tr><td>使用单行注释-comment with line comment</td><td>ctrl + /</td></tr><tr><td>使用/取消多行注释-comment with block comment</td><td>ctrl + shift + /</td></tr><tr><td>选中数行，整体往后移动-tab</td><td>tab</td></tr><tr><td>选中数行，整体往前移动-prev tab</td><td>shift + tab</td></tr></tbody></table><h2 id="2-Debug快捷键"><a href="#2-Debug快捷键" class="headerlink" title="2-Debug快捷键"></a><strong>2-Debug快捷键</strong></h2><table><thead><tr><th>说明</th><th>快捷键</th></tr></thead><tbody><tr><td>单步调试（不进入函数内部）- step over</td><td>F8</td></tr><tr><td>单步调试（进入函数内部）- step into</td><td>F7</td></tr><tr><td>强制单步调试（进入函数内部） - force step into</td><td>alt+shift+f7</td></tr><tr><td>选择要进入的函数 - smart step into</td><td>shift + F7</td></tr><tr><td>跳出函数 - step out</td><td>shift + F8</td></tr><tr><td>运行到断点 - run to cursor</td><td>alt + F9</td></tr><tr><td>继续执行，进入下一个断点或执行完程序 - resume program</td><td>F9</td></tr><tr><td>停止 - stop</td><td>Ctrl+F2</td></tr><tr><td>查看断点 - view breakpoints</td><td>Ctrl+Shift+F8</td></tr><tr><td>关闭 - close</td><td>Ctrl+F4</td></tr></tbody></table><p><strong>转载来源：</strong></p>]]></content>
<categories>
<category> 工具 </category>
</categories>
<tags>
<tag> IDE </tag>
<tag> IntelliJ IDEA </tag>
<tag> 快捷键 </tag>
<tag> 效率提升 </tag>
</tags>
</entry>
<entry>
<title>欢迎使用Hexo</title>
<link href="/2024/04/01/huan-ying-shi-yong-hexo/"/>
<url>/2024/04/01/huan-ying-shi-yong-hexo/</url>
<content type="html"><![CDATA[<p>Welcome to <a href="https://hexo.io/">Hexo</a>! This is your very first post. Check <a href="https://hexo.io/docs/">documentation</a> for more info. If you get any problems when using Hexo, you can find the answer in <a href="https://hexo.io/docs/troubleshooting.html">troubleshooting</a> or you can ask me on <a href="https://github.com/hexojs/hexo/issues">GitHub</a>.</p><h2 id="Quick-Start"><a href="#Quick-Start" class="headerlink" title="Quick Start"></a>Quick Start</h2><h3 id="Create-a-new-post"><a href="#Create-a-new-post" class="headerlink" title="Create a new post"></a>Create a new post</h3><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">$ hexo new <span class="token string">"My New Post"</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>More info: <a href="https://hexo.io/docs/writing.html">Writing</a></p><h3 id="Run-server"><a href="#Run-server" class="headerlink" title="Run server"></a>Run server</h3><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">$ hexo server<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>More info: <a href="https://hexo.io/docs/server.html">Server</a></p><h3 id="Generate-static-files"><a href="#Generate-static-files" class="headerlink" title="Generate static files"></a>Generate static files</h3><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">$ hexo generate<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>More info: <a href="https://hexo.io/docs/generating.html">Generating</a></p><h3 id="Deploy-to-remote-sites"><a href="#Deploy-to-remote-sites" class="headerlink" title="Deploy to remote sites"></a>Deploy to remote sites</h3><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash">$ hexo deploy<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>More info: <a href="https://hexo.io/docs/one-command-deployment.html">Deployment</a></p>]]></content>
<tags>
<tag> Hexo </tag>
</tags>
</entry>
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