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.

socksMerchantProblem.php

//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.

//More details about problem can be found here
//https://www.hackerrank.com/challenges/sock-merchant/problem?h_l=interview&playlist_slugs%5B%5D=interview-preparation-kit&playlist_slugs%5B%5D=warmup

function sockMerchant($n, $ar) {
     // Get the unique version of the array and the count of value appearance.
     $uniqueArrayAndCount = array_count_values($ar);

     //initialize the pair count
    $pairs = 0;

     //iterate over the unique array
    foreach ($uniqueArrayAndCount as $key => $sockCount){
          //if the count is divisible by 2 then its a pair, 
          //divide it and grab the amount of pairs
        if($sockCount % 2 == 0){
            $pairs += $sockCount / 2;
        }else{
          //if the count is not divisible by 2 then it has a loose pair, 
          //find the remainder after dividing by two and remove it from the sum,
          // then divide it by 2 and grab the actual amount of pairs.

            $pairs += ($sockCount - $sockCount % 2) / 2;
        }
    }

    echo $pairs;
}