[LeetCode]Balanced Binary Tree

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.

对每个节点计算该节点的深度，做过左右节点深度相差大于1，false。

 1 /**
 2  * Definition for a binary tree node.
 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     int depthOfTree(TreeNode* root)
13     {
14         if(!root) return 0;
15         return max(depthOfTree(root->left),depthOfTree(root->right))+1;
16     }
17     bool isBalanced(TreeNode* root) {
18         if(!root) return true;
19         if (abs(depthOfTree(root->left)-depthOfTree(root->right))>1) return false;
20         bool left = isBalanced(root->left);
21         bool right = isBalanced(root->right);
22         return left&&right;
23     }
24 };