School Library

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

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

        String[] strings = scanner.nextLine().split("&");
        List<String> books = new ArrayList<>();

        for (String string : strings) {
            books.add(string);
        }

        String command = scanner.nextLine();
        while (!"Done".equals(command)) {
            String[] tokens = command.split("\\s+\\| ");
            String input = tokens[0];

            switch (input) {
                case "Add Book":

                    if (!books.contains(tokens[1])) {
                        books.add(0, tokens[1]);
                    }
                    break;
                case "Take Book":

                    if (books.contains(tokens[1])) {
                        books.remove(tokens[1]);
                    }
                    break;
                case "Swap Books":
                    String book1 = tokens[1];
                    String book2 = tokens[2];
                    int book1Index = books.indexOf(book1);
                    int book2Index = books.indexOf(book2);
                    books.set(book1Index, book2);
                    books.set(book2Index, book1);
                    break;
                case "Insert Book":
                    books.add(tokens[1]);
                    break;
                case "Check Book":
                    int index = Integer.parseInt(tokens[1]);
                    if (index >= 0 && index <= books.size()) {
                        System.out.println(books.get(index));
                    }
                    break;
            }

            command = scanner.nextLine();
        }

        System.out.println(String.join(", ", books));


    }
}