剑指Offer_编程题58：对称的二叉树

题目：请实现一个函数，用来判断一颗二叉树是不是对称的。注意，如果一个二叉树同此二叉树的镜像是同样的，定义其为对称的。

牛客网：链接

# -*- coding:utf-8 -*-
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
class Solution:
    def Symmetrical(self, left, right):
        if not left and not right:
            return True
        if left and right:
            return left.val == right.val and self.Symmetrical(left.left, right.right) and self.Symmetrical(left.right, right.left)
    def isSymmetrical(self, pRoot):
        # write code here
        if not pRoot:
            return True
        return self.Symmetrical(pRoot.left, pRoot.right)