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.

JAVA:

/** 
 * Definition for binary tree 
 * public class TreeNode { 
 *     int val; 
 *     TreeNode left; 
 *     TreeNode right; 
 *     TreeNode(int x) { val = x; } 
 * } 
 */ 
public class Solution { 
 
    public boolean isBalanced(TreeNode root) { 
        if (root==null) 
            return true; 
         
        if (Math.abs(get_height(root.left)-get_height(root.right))>1) 
            return false; 
        else 
            return isBalanced(root.left)&&isBalanced(root.right); 
    } 
     
    public int get_height(TreeNode node){ 
        if(node==null) 
            return 0; 
        else  
            return Math.max(get_height(node.left), get_height(node.right))+1; 
    }    
    

//There are two recursions here: one in another. We can remove one by define a global variable RESULT, and assigns value to it when computing the height (by checking the height of its subtrees).

Balanced binary tree

原文：http://www.cnblogs.com/cs-jack-cheng/p/4110338.html