# Longest subarray with absolute difference equal to some number in JavaScript

JavascriptWeb DevelopmentFront End Technology

We are required to write a JavaScript function that takes in an array of Numbers as the first argument, let's say arr, and a number, let's say num, as the second argument. The function should find and return the length of the longest subarray (contiguous or non-contiguous) whose each pair has an absolute difference less than or equal to num.

For example, if the input array and the number are −

const arr = [7, 9, 8, 6, 6, 3];
const num = 1;

Then the output should be −

const output = 3,

because the desired subarray is [7, 6, 6]

## Example

The code for this will be −

Live Demo

const arr = [7, 9, 8, 6, 6, 3];
const maximumSubarray = (arr = [], num = 1) => {
if(!arr.length){
return 0;
};
const maximum = arr.reduce((acc, val) => Math.max(acc, val));
const buckets = new Array(maximum + 1);
buckets.fill(0);
const { length } = arr;
for(let i=0; i< length; i++){
buckets[arr[i]] += num;
};
let max = 0;
for(let j=1; j< maximum + 1; j++) {
let curr = buckets[j];
let prev = buckets[j - 1];
if(prev != 0 && prev + curr > max) {
max = prev + curr;
};
};
return max;
};
console.log(maximumSubarray(arr));

## Output

And the output in the console will be −

3
Published on 24-Feb-2021 05:47:41