码迷,mamicode.com
首页 > 其他好文 > 详细

leetcode - Symmetric Tree

时间:2014-09-28 20:10:56      阅读:178      评论:0      收藏:0      [点我收藏+]

标签:style   color   io   os   ar   for   sp   on   c   

Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).

For example, this binary tree is symmetric:

    1
   /   2   2
 / \ / 3  4 4  3

But the following is not:

    1
   /   2   2
   \      3    3

Note:
Bonus points if you could solve it both recursively and iteratively.

confused what "{1,#,2,3}" means?

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
struct TreeNode
{
	int val;
	TreeNode *left;
	TreeNode *right;
	TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};
class Solution {
public:
    bool isSymmetric(TreeNode *root) {
        if(root == NULL) return true;
		return dfs(root->left,root->right);
    }
private:
	bool dfs(TreeNode *a,TreeNode *b)
	{
		if(a == NULL && b == NULL) return true;
		if((a == NULL && b != NULL) || (a != NULL && b == NULL)) return false;
		return a->val == b->val && dfs(a->left,b->right) && dfs(a->right,b->left);
	}
};


leetcode - Symmetric Tree

标签:style   color   io   os   ar   for   sp   on   c   

原文地址:http://blog.csdn.net/akibatakuya/article/details/39644231

(0)
(0)
   
举报
评论 一句话评论(0
登录后才能评论!
© 2014 mamicode.com 版权所有  联系我们:gaon5@hotmail.com
迷上了代码!