Inverting Binary Tree #LeetCode_June _2020 Challenge Day 1

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First we traverse the tree Using Postorder traversal, we swap left child and right child of each node and return to root this processcan be done using recursion.We define swap function that first processes left subtree and then right sub tree

Python Code:

Method1:

class TreeNode:

    def __init__(self, val=0, left=None, right=None):

       self.val = val

          self.left = left
         self.right = right

class Solution:
    
    def invertTree(self, root: TreeNode) -> TreeNode:
        if root:
            root.left,root.right = root.right,root.left
            self.invertTree(root.left)
            self.invertTree(root.right)

        return root 
Method2:

# Definition for a binary tree node.

class TreeNode:

    def __init__(self, val=0, left=None, right=None):

        self.val = val

        self.left = left

        self.right = right

class Solution:

    def swap(self,root):

        if not root:

            return

        #swap child pointers

        self.swap(root.left)

        self.swap(root.right)

        root.left,root.right = root.right,root.left 

    def invertTree(self, root: TreeNode) -> TreeNode:

        self.swap(root)

        return root
    #Hidden Driver Code

CONCLUSION:
This Algorithms Takes Big O(n) Time Complexity
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