Hackerrank - Sock Merchant Solution
2 min read

Hackerrank - Sock Merchant Solution

Hackerrank - Sock Merchant Solution

John works at a clothing store. He has a large pile of socks that he must pair by color for sale. Given an array of integers representing the color of each sock, determine how many pairs of socks with matching colors there are.

For example, there are  socks with colors . 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. It must return an integer representing the number of matching pairs of socks that are available.

sockMerchant has the following parameter(s):

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

Input Format

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


  • where

Output Format

Return the total number of matching pairs of socks that John can sell.

Sample Input

10 20 20 10 10 30 50 10 20

Sample Output




John can match three pairs of socks.

Solution in Python

from collections import Counter

def sockMerchant(n,arr):
    n = Counter(arr)
    return sum(i//2 for i in n.values())

n = input()
arr = list(map(int,input().split()))


We first take input from user

>>> arr = list(map(int,input().split()))
>>> arr
[10, 20, 20, 10, 10, 30, 50, 10, 20]

Then we use Counter to group and count all similar type of socks

>>> n = Counter(arr)
>>> n
Counter({10: 4, 20: 3, 30: 1, 50: 1})
>>> n.values()
dict_values([4, 3, 1, 1])

Now we just have to loop through n.values() and divide by 2 which gives us total possible pairs

4//2 = 2

3//2 = 1

1//2 =0

1//2 =0

Total pairs = 2 + 1 + 0 +0 = 3

>> sum(i//2 for i in n.values())

Enjoying these posts? Subscribe for more

Adblocker detected! Please consider reading this notice.

We've detected that you are using AdBlock Plus or some other adblocking software which is preventing the page from fully loading.

That's okay. But without advertising-income, we can't keep making this site awesome.

We don't have any banner, Flash, animation, obnoxious sound, or popup ad. We do not implement these annoying types of ads!

We need money to operate the site, and almost all of it comes from our online advertising.

Please add thepoorcoder.com to your ad blocking whitelist or disable your adblocking software.