[LeetCode] Balanced Binary Tree 深度搜索

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 <iostream>
#include <stdlib.h>
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;
}