Balanced Binary Tree

Given a binary tree, determine if it is

public class Solution {public boolean NotBalancedflag;public boolean isBalanced(TreeNode root) {// IMPORTANT: Please reset any member data you declared, as// the same Solution instance will be reused for each test case.NotBalancedflag = false;checkBalanced(root);if (NotBalancedflag)return false;elsereturn true;}public int checkBalanced(TreeNode root) {if (NotBalancedflag == true)return -1;if (root == null)return 0;int leftDepth = checkBalanced(root.left);int rightDepth = checkBalanced(root.right);if (java.lang.Math.abs(leftDepth - rightDepth) > 1) {NotBalancedflag = true;}return java.lang.Math.max(leftDepth, rightDepth) + 1;}}

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.