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.

Code

public class Solution {
    public boolean isBalanced(TreeNode root) {
        return maxDepth(root)!=-1;
    }

    private int maxDepth(TreeNode root){
        if (root==null) return 0;
        int left = maxDepth(root.left);
        if (left==-1) return -1;
        int right = maxDepth(root.right);
        if (right==-1) return -1;
        return (Math.abs(left-right)<=1) ? Math.max(left,right)+1 : -1;

    }

}