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         return findDeep(root)!=-1;
14     }
15     
16     int findDeep(TreeNode* root)
17     {
18         int i_deepL=0,i_deepR=0;
19         if(root==nullptr)
20         {
21             return 0;
22         }
23         i_deepL+=findDeep(root->left);
24         i_deepR+=findDeep(root->right);
25         if(i_deepL==-1||i_deepR==-1)
26         {
27             return -1;
28         }
29         if(i_deepL-i_deepR>1||i_deepR-i_deepL>1)
30         {
31             return -1;
32         }
33         return max(i_deepL,i_deepR)+1;          //加上本层的高度
34     }
35 };