/** * 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) {
        int h=isBal(root);
        if(h!=-1){
            return true;
        }
        else{
            return false;
        }
    }

    public int isBal(TreeNode root){
        if(root==null){
            return 0;
        }
        else{
            int left=isBal(root.left);
            int right=isBal(root.right);
            if(left!=-1&&right!=-1&&Math.abs(left-right)<=1){
                return Math.max(left,right)+1;
            }
            else{
                return -1;
            }
        }
    }
}