题解 | #对称的二叉树#

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