Leetcode 226. Invert Binary Tree

Posted 2020-08-20 lettuan

Invert a binary tree.

     4
   /     2     7
 / \   / 1   3 6   9

to

     4
   /     7     2
 / \   / 9   6 3   1

 1 class Solution(object):
 2     def invertTree(self, root):
 3         """
 4         :type root: TreeNode
 5         :rtype: TreeNode
 6         """
 7         if not root:
 8             return
 9         
10         root.left, root.right = root.right, root.left
11         self.invertTree(root.right)
12         self.invertTree(root.left)
13         
14         return root
15