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.

 

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　　一个深度搜索的问题。

 

#include 
      
       #include 
       
        using namespace std;/** * Definition for binary tree */struct TreeNode {    int val;    TreeNode *left;    TreeNode *right;    TreeNode(int x) : val(x), left(NULL), right(NULL) {}};class Solution {public:    bool isBalanced(TreeNode *root) {        if(root==NULL)  return true;        if(help_fun(root)<0)    return false;        return  true;    }    int help_fun(TreeNode *node)    {        if(node==NULL)  return 0;        int lft = help_fun(node->left);        int rgt = help_fun(node->right);        if(lft==-1 ||rgt==-1)   return -1;        if(abs(lft-rgt)<2)            return (lft>rgt?lft:rgt) +1;        else            return -1;     }};int main(){    return 0;}