Sales by Match HackerRank Problem Solution

Sales by Match Hacker Rank Problem Solution
Sales by Match Hacker Rank Problem Solution

In this Sales by Match HackerRank Problem, There is a large pile of socks that must be paired by color. Given an array of integers representing the color of each sock, determine how many pairs of socks with matching colors there are.


There is one pair of color  and one of color . There are three odd socks left, one of each color. The number of pairs is .

Function Description

Complete the sockMerchant function in the editor below.

sockMerchant has the following parameter(s):

  • int n: the number of socks in the pile
  • int ar[n]: the colors of each sock


  • int: the number of pairs

Input Format

The first line contains an integer , the number of socks represented in .
The second line contains  space-separated integers, , the colors of the socks in the pile.


  •  where 

Sample Input

STDIN                       Function
-----                       --------
9                           n = 9
10 20 20 10 10 30 50 10 20  ar = [10, 20, 20, 10, 10, 30, 50, 10, 20]

Sample Output




There are three pairs of socks.

Sales by Match HackerRank Problem Solutions

I will Provide solution in Multiple programming languages for you. If you are not able to find the code in required language then please share in comments so that our team can help you.

Problem Solution in JavaScript

function sockMerchant(n, ar) {
  let equal = 0;
  const variants = new Set(ar);
  let pairCount = [];
    for(let i=0; i<ar.length;i++){
      if(value == ar[i]){
        equal +=1;
    equal = 0;

  pairCount = => Math.floor(item/2));
  pairCount = pairCount.reduce((acc, val) => acc+val,0);
  return pairCount;

Sales by Match Problem Solution in Python

def sockMerchant(n, ar):

  color_dict = dict()

  # Count the number of socks for each color
  for i in range(len(ar)):
      if ar[i] in color_dict:
          color_dict[ar[i]] +=1
          color_dict[ar[i]] = 1

  # Find the total number of pairs
  nb_pairs = 0
  for value in color_dict.values():
      nb_pairs += int(value/2)

  return nb_pairs

Problem Solution in Java

public static int sockMerchant(int n, List ar) {

    int counter = 0;

    for (int i = ar.size() - 1; i >=1; i--) {
        if (ar.get(i).equals( ar.get(i - 1))){
            i = i -1;

    return counter;

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