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.

 

C++实现代码：

#include<iostream>

#include<new>

#include<vector>

#include<cmath>

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;

        int lhigh=maxDepth(root->left);

        int rhigh=maxDepth(root->right);

        if(abs(lhigh-rhigh)>1)

            return false;

        return isBalanced(root->left)&&isBalanced(root->right);

    }

    int maxDepth(TreeNode *root)

    {

        if(root)

        {

            if(root->left==NULL&&root->right==NULL)

                return 1;

            int leftDepth=maxDepth(root->left);

            int rightDepth=maxDepth(root->right);

            return leftDepth>= rightDepth ?(leftDepth+1):(rightDepth+1);

        }

        return 0;

    }

    void createTree(TreeNode *&root)

    {

        int i;

        cin>>i;

        if(i!=0)

        {

            root=new TreeNode(i);

            if(root==NULL)

                return;

            createTree(root->left);

            createTree(root->right);

        }

    }

};



int main()

{

    Solution s;

    TreeNode *root;

    s.createTree(root);

    cout<<s.maxDepth(root);

    cout<<endl;

    cout<<s.isBalanced(root)<<endl;

}