P3_HouseParty_Lists_Ex

package feb20_Lists_Exercises;

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class P3_HouseParty {
    public static void main(String[] args) {
        @SuppressWarnings("resource")

        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.nextLine());

        List<String> names = new ArrayList<>();

        for (int i = 1; i <= n; i++) {
            String inputData = sc.nextLine();
            String[] input = inputData.split("\\s+");

            String name = input[0];

            if (input.length == 3) {
                if (!names.contains(name)) {
                    names.add(name);
                } else {
                    System.out.printf("%s is already in the list!%n", name);
                }
            } else if (input.length == 4) {
                if (names.contains(name)) {
                    names.remove(name);
                } else {
                    System.out.printf("%s is not in the list!%n", name);
                }
            }
        }

        String output = names.toString().replaceAll("\\[|,|\\]", "");
        System.out.println(output.replaceAll("\\s+", "\n"));
    }
}