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
#
class Solution:
    def Mirror(self , pRoot: TreeNode) -> TreeNode:
        # write code here
        if not pRoot:
            return None
        
        pRoot.left, pRoot.right = pRoot.right, pRoot.left

        if (pRoot.left):
            self.Mirror(pRoot.left)

        if (pRoot.right):
            self.Mirror(pRoot.right)

        return pRoot

!!! 交换左右子树时，不仅交换结点，还交换结点的所有子结点。

ref:

https://blog.csdn.net/qq_36421001/article/details/122965732