58.对称的二叉树(python)

Posted 2020-11-25 Assange

题目描述

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。

 1 class Solution:
 2     def isSymmetrical(self, pRoot):
 3         # write code here
 4         def mirror(left,right):
 5             if left == None and right == None:
 6                 return True
 7             elif left == None or right == None:
 8                 return False
 9             if left.val != right.val:
10                 return False
11             ret1 = mirror(left.left,right.right)
12             ret2 = mirror(left.right,right.left)
13             return ret1 and ret2
14         if pRoot == None:
15             return True
16         return mirror(pRoot.left,pRoot.right)

2020-01-01 09:32:41