[Hackerrank] Solution of Divisible Sum Pairs in JavaScript

hackerrank_solution_of_divisible_sum_pairs_in_javascript.js

function divisibleSumPairs(n, k, ar) {
	let result = 0;
	for(let i = 0; i < n - 1; i++) {
  	result += ar.slice(i + 1, n).filter((item, index) => {
    	if ((item + ar[i]) % k === 0) {
    		return item;
      }
    }).length;
  }
  return result;
}

for(let i = 0; i < n; i++) {
for(let j = i + 1; j < n; j++ ) {
let sum = ar[i] + ar[j]
if(sum % k === 0) {
counter++
}
}
this does not work for single element ... the following code will work

function divisibleSumPairs(n, k, ar) {
// Write your code here
var sum = 0;
var pair = 0;

// for single element array where the element is divisible by k
if(n==1 && (ar[0]%k == 0)){
   pair = 1;
}
else if (n > 1){
    for(i = 0; i<n; i++){
        // for adding the values
        for(j = i+1; j<n; j++){
            sum = ar[i] + ar[j];
            if(sum % k == 0){
                pair++;
                // console.log("I am pair", pair);
            }
        }
    }
    
}
    
else {
    pair = 0;
}

return pair;

}