Picking Numbers - HakerRank Solution - Javascript

Given an array of integers, find the longest subarray where the absolute difference between any two elements is less than or equal to

Example

_a = [1,1,2,2,4,4,5,5,5]_
There are two subarrays meeting the criterion: [1,1,2,2] and [4,4,5,5,5]. The maximum length subarray has 5 elements.

Function Description

Complete the pickingNumbers function in the editor below.

pickingNumbers has the following parameter(s):

• int a[n]: an array of integers

Returns

• int: the length of the longest subarray that meets the criterion

Input Format

The first line contains a single integer n, the size of the array a.
The second line contains n space-separated integers, each an a[i].

Solution

function pickingNumbers(a) {
    // Create an array to store frequency of each element in the input array
    let frequency = new Array(100).fill(0);

    // Count frequency of each element
    for (let i = 0; i < a.length; i++) {
        frequency[a[i]]++;
    }

    // Initialize a variable to store the maximum length of subarray found
    let maxLength = 0;

    // Traverse through frequency array to find the longest subarray
    for (let i = 1; i < frequency.length; i++) {
        // The length of a valid subarray is the sum of the frequency of
        // the current element and the previous element
        maxLength = Math.max(maxLength, frequency[i] + frequency[i - 1]);
    }

    return maxLength;
}