[LeetCode]#226. Invert Binary Tree

Environment: Python 3.8

Key technique: binarytree module, Recursive

Invert a binary tree.

Example:

Input:

4
   /   \
  2     7
 / \   / \
1   3 6   9

Output:

4
   /   \
  7     2
 / \   / \
9   6 3   1

Analysis:

1. Invert [2,1,3] and [7,6,9] node
2. Invert [6] and [9] and [1] and [3].
3. Return root

Solution:

class Solution(object):
    def invertTree(self, root):
if not root:
            return
        
        temp = root.left
        root.left = root.right
        root.right = temp
        
        self.invertTree(root.left)
        self.invertTree(root.right)
        
        return root

Submissions:

Reference:

https://leetcode.com/problems/invert-binary-tree/discuss/1034130/Simple-Python-Recursive-Solution