04. List Operations

import java.util.*;
import java.util.stream.Collectors;

public class demo {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
       List<Integer> numbers = Arrays.stream(scanner.nextLine().split("\\s+"))
               .map(Integer::parseInt).collect(Collectors.toList());

       String input = scanner.nextLine();

       while(!input.equals("End")) {
           String[] tokens = input.split("\\s+");
           String command = tokens[0];
           switch(command) {
               case "Add":
                   //"Add 10" -> ["Add", "10"]
                   int numberToAdd = Integer.parseInt(tokens[1]);
                   numbers.add(numberToAdd);
                   break;
               case "Insert":
                   //"Insert 3 0" -> ["Insert", "3", "0"]
                   int addNumber = Integer.parseInt(tokens[1]);
                   int index = Integer.parseInt(tokens[2]);
                   //validate index
                   if(isValidIndex(index, numbers.size())) {
                       numbers.add(index, addNumber);
                   } else {
                       System.out.println("Invalid index");
                   }
                   break;
               case "Remove":
                   //"Remove 2" -> ["Remove", "2"]
                   int indexRemove = Integer.parseInt(tokens[1]);
                   //validate index
                   if(isValidIndex(indexRemove, numbers.size())) {
                    numbers.remove(indexRemove);
                   } else {
                       System.out.println("Invalid index");
                   }

                   break;
               case "Shift":
                   //"Shift right 5" -> ["Shift", "right", "5"]
                   //"Shift left 5" -> ["Shift", "left", "5"]
                   String direction = tokens[1];
                   int count = Integer.parseInt(tokens[2]);
                   if(direction.equals("right")) {
                       for (int i = 1; i <= count ; i++) {
                           //последния става първи
                           //1. последния
                           //1 23 29 18 43 21
                           int lastNumber = numbers.get(numbers.size() - 1);
                           numbers.remove(numbers.size() - 1);
                           numbers.add(0, lastNumber);
                       }

                   } else if (direction.equals("left")) {
                       for (int i = 1; i <= count ; i++) {
                           int firstNumber = numbers.get(0);
                           numbers.remove(0);
                           numbers.add(firstNumber);
                       }
                   }
                   break;
           }

           input = scanner.nextLine();
       }
        printList(numbers);


    }

    private static boolean isValidIndex(int index, int length) {
        return index >= 0 && index <= length - 1;

    }


    private static void printList(List<Integer> wagons) {
        for (int wagon : wagons) {
            System.out.print(wagon + " ");
        }
    }
}