In java 8:

public static int sockMerchant(int n, List ar) { // Write your code here Integer pairs = 0; int i = 0; while(i < (ar.size() - 1)) { Integer sock = ar.get(i); for(int j = i+1; j < ar.size(); j++){ if(sock == ar.get(j)){ pairs++; ar.remove(i); ar.remove(j - 1); break; }

            if(j == (ar.size() - 1)){
                ar.remove(i);
            }
        }
    }
    return pairs;   
}

}