update

src/49.group-anagrams.cc

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+// Copyright (c) 2024 The Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Authors: liubang ([email protected])
+
+#include <gtest/gtest.h>
+
+#include <algorithm>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+namespace {
+class Solution {
+public:
+    std::vector<std::vector<std::string>> groupAnagrams(const std::vector<std::string>& strs) {
+        std::unordered_map<std::string, std::vector<std::string>> map;
+        for (const auto& str : strs) {
+            if (str.empty()) {
+                map[str].push_back(str);
+            } else {
+                std::string copy = str;
+                std::sort(copy.begin(), copy.end());
+                map[copy].push_back(str);
+            }
+        }
+        std::vector<std::vector<std::string>> result;
+        result.reserve(map.size());
+        for (const auto& [k, v] : map) {
+            result.emplace_back(v);
+        }
+        return result;
+    }
+};
+} // namespace
+
+TEST(Leetcode, group_anagrams) {
+    Solution s;
+    {
+        std::vector<std::vector<std::string>> exp = {
+            {"bat"}, {"tan", "nat"}, {"eat", "tea", "ate"}};
+        EXPECT_EQ(exp, s.groupAnagrams({"eat", "tea", "tan", "ate", "nat", "bat"}));
+    }
+    {
+        std::vector<std::vector<std::string>> exp = {{""}};
+        EXPECT_EQ(exp, s.groupAnagrams({""}));
+    }
+    {
+        std::vector<std::vector<std::string>> exp = {{"a"}};
+        EXPECT_EQ(exp, s.groupAnagrams({"a"}));
+    }
+}