【LeetCode】226. 左右颠倒二叉树

问题描述

Invert a binary tree.

颠倒一个二叉树

输入:

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

输出:

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

Python 实现

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution(object):
    def invertTree(self, root):
        """
        :type root: TreeNode
        :rtype: TreeNode
        """
        if root == None:
            return None
        else:
            tNode = root.left
            root.left = self.invertTree(root.right)
            root.right = self.invertTree(tNode)
            return root
            

链接：https://leetcode.com/problems/invert-binary-tree/