剑指offer-二叉树的镜像-python

题目描述

操作给定的二叉树，将其变换为源二叉树的镜像。

输入描述:

二叉树的镜像定义：源二叉树 
    	    8
    	   /  \
    	  6   10
    	 / \  / \
    	5  7 9   11
    	镜像二叉树
    	    8
    	   /  \
    	  10   6
    	 / \  / \
    	11 9 7   5
思路：
使用递归将左右子树交换

# -*- coding:utf-8 -*-
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
class Solution:
    # 返回镜像树的根节点
    def Mirror(self, root):
        # write code here
        return self.swap(root)
    def swap(self,tree):
        if not tree:
            return 
        temp = tree.left
        tree.left = self.swap(tree.right)
        tree.right = self.swap(temp)
        return tree