题解 | #二叉树的镜像#

# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param pRoot TreeNode类 
# @return TreeNode类
#
from collections import deque

class Solution:
    def Mirror(self , pRoot: TreeNode) -> TreeNode:
        # write code here
        if not pRoot:
            return None
        queue = deque()
        queue.append(pRoot)
        while queue:
            for _ in range(len(queue)):
                node = queue.popleft()
                node.left, node.right = node.right, node.left
                if node.left: queue.append(node.left)
                if node.right: queue.append(node.right)
        return pRoot

背诵层次遍历模板，直接对调node的left和right即可。