1346. Check If N and Its Double Exist | LeetCode Solution | JavaScript | Easy

LeetCode Problem - Link

Problem

Given an array arr of integers, check if there exist two indices i and j such that :

• i != j
• 0 <= i, j < arr.length
• arr[i] == 2 * arr[j]

Example 1:

Input: arr = [10,2,5,3]
Output: true
Explanation: For i = 0 and j = 2, arr[i] == 10 == 2 * 5 == 2 * arr[j]

Bruteforce

This is the only code that I could get to work. I couldn't optimize this to j=i+1 for example.

/**
 * @param {number[]} arr
 * @return {boolean}
 */
var checkIfExist = function (arr) {
    for (var i = 0; i < arr.length; i++) {
        for (var j = 0; j < arr.length; j++) {
            if (arr[i] == arr[j] * 2 && i != j) {
                return true
            }
        }
    }

    return false
};