剑指Offer 28 对称的二叉树

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 # -*- coding:utf-8 -*-
 2 # class TreeNode:
 3 #     def __init__(self, x):
 4 #         self.val = x
 5 #         self.left = None
 6 #         self.right = None
 7 class Solution:
 8     def isSameTree(self,left,right):
 9         if left != None and right != None:
10             if left.val != right.val:
11                 return False
12             else:
13                 return self.isSameTree(left.left,right.right) and self.isSameTree(left.right,right.left)
14         if left == None and right == None:
15             return True
16         else:
17             return False
18         
19     def isSymmetrical(self, pRoot):
20         if pRoot == None:
21             return True
22         return self.isSameTree(pRoot.left,pRoot.right)
23         # write code here

Java版，leetcode地址：

 1 class Solution {
 2     public boolean isSameTrees(TreeNode left, TreeNode right) {
 3         if (left == null && right == null) {
 4             return true;
 5         } else if (left != null && right != null) {
 6             if (left.val != right.val) {
 7                 return false;
 8             } else {
 9                 return isSameTrees(left.left, right.right) && isSameTrees(left.right, right.left);
10             }
11         } else {
12             return false;
13         }
14     }
15 
16     public boolean isSymmetric(TreeNode root) {
17         if (root == null) {
18             return true;
19         } else {
20             return isSameTrees(root.left, root.right);
21         }
22     }
23 }

posted on 2019-06-13 14:42 Sempron2800+ 阅读(117) 评论(0) 编辑收藏举报