O3. Memory Game / O1. Mid Exam Retake

package MidExam.O1;

import java.util.Arrays;
import java.util.List;
import java.util.Scanner;
import java.util.stream.Collectors;

public class O3MemoryGame {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        List<String> testList = Arrays.stream(scanner.nextLine().split("\\s+")).
                map(String::toString).collect(Collectors.toList());

        String input = scanner.nextLine();
        int counters = 0;
        while (!input.equals("end")) {
            if (testList.size() == 0) {
                break;
            }
            List<String> command = Arrays.asList(input.split("\\s+"));
            int a = Integer.parseInt(command.get(0));
            int b = Integer.parseInt(command.get(1));
            counters += 1;
            if (Math.min(a, b) < 0 || a == b || Math.max(a, b) >= testList.size()) {

                int center = testList.size() / 2;
                testList.add(center, "-" + counters + "a");
                testList.add(center, "-" + counters + "a");
                System.out.println("Invalid input! Adding additional elements to the board");

            } else if (testList.get(a).equals(testList.get(b))) {

                String element = testList.get(a);
                testList.remove(Math.min(a, b));
                testList.remove(Math.max(a, b) - 1);
                System.out.printf("Congrats! You have found matching elements - %s!%n", element);

            } else {
                System.out.println("Try again!");
            }
            input = scanner.nextLine();
        }
        if (testList.size() == 0) {
            System.out.printf("You have won in %d turns!", counters);
        } else {
            System.out.println("Sorry you lose :(");
            for (String s : testList) {
                System.out.print(s + " ");
            }
        }
    }
}