Hackerrank Sales by Match Solution - Java For Explanation watch video : Code:: import java.io.*; import java.math.*; import java.security.*; import java.text.*; import java.util.*; import java.util.concurrent.*; import java.util.function.*; import java.util.regex.*; import java.util.stream.*; import static java.util.stream.Collectors.joining; import static java.util.stream.Collectors.toList; class Result { /* * Complete the 'sockMerchant' function below. * * The function is expected to return an INTEGER. * The function accepts following parameters: * 1. INTEGER n * 2. INTEGER_ARRAY ar */ public static int sockMerchant( int n, List<Integer> ar) { int count = 0 ; HashSet<Integer> hs = new HashSet<>(); for ( int i= 0 ;i<n;i++){ int num = ar.get(i); if (!hs.contains(num)){ hs.add(num); } else {