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ZeeshanAli-0704

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# 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 left and right subtrees of every node differ in height by no more than 1.

Input: root = [3,9,20,null,null,15,7]
Output: true

``````/**
* Definition for a binary tree node.
* function TreeNode(val, left, right) {
*     this.val = (val===undefined ? 0 : val)
*     this.left = (left===undefined ? null : left)
*     this.right = (right===undefined ? null : right)
* }
*/
/**
* @param {TreeNode} root
* @return {boolean}
*/
var isBalanced = function(root) {
let flag = true;

var height = function(r){
if(!r) return 0;

let num1 = height(r.left);
let num2 = height(r.right);
let res = num1 - num2;

if(res < -1 || res > 1) flag = false;

return Math.max(num1,num2) + 1;
}

height(root);
return flag;
};
``````