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.

Solution:

/**
 * Definition for a binary tree node.
 * 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;
        return  height(root)!=-1;
    }
    public int height(TreeNode root){
        if(root==null) return 0;
        int leftH = height(root.left);
        if(leftH==-1) return -1;
        int rightH = height(root.right);
        if(rightH==-1) return -1;
        if(Math.abs(leftH-rightH)>1) return -1;
        return Math.max(leftH, rightH) + 1;
    }
}