LeetCode OJ：Balanced Binary Tree（平衡二叉树）

 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     bool isBalanced(TreeNode* root) {
13         int dep;
14         checkBalance(root, dep);
15     }
16     bool checkBalance(TreeNode * root, int &dep)
17     {
18         if(root == NULL){
19             dep = 0;
20             return true;
21         }
22         int leftDep, rightDep;
23         bool isLeftBal = checkBalance(root->left, leftDep);
24         bool isRightBal = checkBalance(root->right, rightDep);
25 
26         dep = max(leftDep, rightDep) + 1;
27         return isLeftBal && isRightBal && (abs(leftDep - rightDep) <= 1);
28     }
29 };