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trees.py
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trees.py
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class Node:
def __init__(self, data):
self.left = None
self.right = None
self.data = data
class BST:
def __init__(self):
self.root = None
def insert(self, data, parent):
if self.root == None:
node = Node(data)
self.root = node
#print(self.root.data,"root of tree")
return
elif data == parent.data:
return
elif data < parent.data:
if parent.left == None: # if root ka left child does't exist
node = Node(data)
parent.left = node
return
else:
self.insert(data, parent.left)
elif data > parent.data:
if parent.right == None:
node = Node(data)
parent.right = node
return
else:
self.insert(data, parent.right)
def inorder(self, parent):
""" Left Parent Right"""
if parent == None:
return
elif parent: # if left child is there
self.inorder(parent.left)
print(parent.data, end=" ")
self.inorder(parent.right)
def preorder(self, parent):
""" Parent Left Right"""
if parent == None:
return
elif parent:
print(parent.data, end=" ")
self.preorder(parent.left)
self.preorder(parent.right)
def postorder(self, parent):
"""Left Right Parent """
if parent == None:
return
elif parent:
self.postorder(parent.left)
self.postorder(parent.right)
print(parent.data, end=" ")
def levelorder(self, parent):
"""BFS"""
q = []
q.append(parent)
while q:
node = q.pop(0)
print(node.data, end=" ")
if node.left:
q.append(node.left)
if node.right:
q.append(node.right)
def height(self, parent):
if parent == None:
return 0
else:
height_tree = 1 + max(self.height(parent.left),
self.height(parent.right))
return height_tree
def min_max_element(self, parent):
'''min element will be bottommost element of LST and max at the RST'''
def get_min(parent):
if parent.left:
return get_min(parent.left)
else:
return parent
def get_max(parent):
if parent.right:
return get_max(parent.right)
else:
return parent
return (get_min(parent),get_max(parent))
def find(self,parent,x):
if parent:
if parent.data==x:
return parent #returning node
if x< parent.data:
return self.find(parent.left,x)
if x>parent.data:
return self.find(parent.right,x)
return None
else:
return None
def get_distance(self,parent,x):
''' It is assumed that x exist in tree otherwise we will use find to check'''
if parent:
if parent.data==x:
return 0
if x<parent.data and parent.left:
return 1+ self.get_distance(parent.left,x)
if x>parent.data and parent.right:
return 1+ self.get_distance(parent.right,x)
return 0
else:
return 0
def checkleaf(self,parent,x):
node = self.find(parent,x)
if node.left==None and node.right==None:
return node
else:
return None
def checkSingleChild(self,parent,x):
node = self.find(parent,x)
if (node.left and node.right==None) or (node.left==None and node.right):
return node
else:
return None
def checkTwoChild(self,parent,x):
node = self.find(parent,x)
if node.left and node.right:
return node
else:
return None
def get_parent(self,parent,node): #here parent refers to current node
''' IT IS ASSUMED THAT NODE WILL EXIST IN TREE'''
if parent.left==node or parent.right == node: #checking left and right child of current node
return parent
if node.data<parent.data:
return self.get_parent(parent.left,node)
if node.data>parent.data:
return self.get_parent(parent.right,node)
def delete(self,parent,x):
''' checking if node is leaf node '''
node = self.checkleaf(parent,x)
if node:
parent_node=self.get_parent(parent,node)
if parent_node.left==node:
parent_node.left=None
else:
parent_node.right=None
return
''' if it is not leaf node then we check if it is single child '''
node = self.checkSingleChild(parent,x) #here node has either left child or right child
if node:
parent_node=self.get_parent(parent,node)
if parent_node.right == node: # if node is parent's right child then we will set parent's right with the child of node
if node.left:
parent_node.right = node.left
elif node.right:
parent_node.right = node.right
elif parent_node.left == node:
if node.left:
parent_node.left = node.left
elif node.right:
parent_node.left = node.right
return
''' check if it is has 2 child '''
node = self.checkTwoChild(parent,x)
inorderSuccessor = self.min_max_element(node.right)[0] #getting minimum value node in right sub tree
#print(inorderSuccessor.data,"inorder daat")
parent_node=self.get_parent(parent,node)
parent_node.right.data = inorderSuccessor.data #copying inorder's data to parent's right
#finally deleting inordersuccessorS
''' NOT POSSIBLE IN THIS AS single function is handling all the 3 cases '''
array = [67, 34, 80, 12, 45, 78, 95, 10, 38, 60, 86]
tree = BST()
root=tree.root
for i in array:
tree.insert(i, tree.root)
print("Inorder->", tree.inorder(tree.root))
'''
print("Preorder",tree.preorder(tree.root))
print("Postorder",tree.postorder(tree.root))
print("level Order",tree.levelorder(tree.root))
print("Height of tree", tree.height(tree.root))
min_max= tree.min_max_element(tree.root)
print("Minimum element:",min_max[0] ,"Maximum element:",min_max[1])
print("checking if 15 in tree:", tree.find(tree.root,15))
print("getting distance from root node", tree.get_distance(tree.root,60))
'''
tree.delete(tree.root,80)
print("Inorder->", tree.inorder(tree.root))