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LeetCode: Balanced Binary Tree

Given a binary tree, determine if it is height-balanced.

For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1.

地址:https://oj.leetcode.com/problems/balanced-binary-tree/

算法:递归解决,并且在递归的过程中求出树的深度。代码:

 1 /**
 2  * Definition for binary tree
 3  * struct TreeNode {
 4  *     int val;
 5  *     TreeNode *left;
 6  *     TreeNode *right;
 7  *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 8  * };
 9  */
10 class Solution {
11 public:
12     bool isBalanced(TreeNode *root) {
13         if(!root){
14             return true;
15         }
16         int depth = 0;
17         return subIsBalanced(root,depth);
18     }
19     bool subIsBalanced(TreeNode *root, int &depth){
20         if(!root){
21             depth = 0;
22             return true;
23         }
24         int left_depth;
25         bool left = subIsBalanced(root->left,left_depth);
26         int right_depth;
27         bool right = subIsBalanced(root->right,right_depth);
28         depth = left_depth > right_depth ? left_depth + 1 : right_depth + 1;
29         if(left && right){
30             if(left_depth > right_depth + 1 || right_depth > left_depth + 1){
31                 return false;
32             }
33             return true;
34         }
35         return false;
36     }
37 };

 

posted on 2014-08-27 21:02  Boostable  阅读(272)  评论(0编辑  收藏  举报