Problem3

using System;
using System.Collections.Generic;
using System.Linq;

namespace Problem3
{
    class Program
    {
        static void Main(string[] args)
        {
            List<string> cards = Console.ReadLine()
                .Split(":", StringSplitOptions.RemoveEmptyEntries)
                .ToList();

            List<string> deck = new List<string>();

            while (true)
            {
                string line = Console.ReadLine();

                if (line == "Ready")
                {
                    break;
                }

                string[] tokens = line.Split(' ', StringSplitOptions.RemoveEmptyEntries);

                string command = tokens[0];

                if (command == "Add")
                {
                    string cardName = tokens[1];

                    if (Exist(cards, cardName))
                    {
                      deck.Add(cardName);
                    }
                    else
                    {
                        Console.WriteLine("Card not found.");
                    }
                }
                else if (command == "Insert")
                {
                    string cardName = tokens[1];
                    int index = int.Parse(tokens[2]);

                    if (Exist(cards, cardName) &&
                        IsValidIndex(cards, index))
                    {
                        deck.Insert(index, cardName);
                    }
                    else
                    {
                        Console.WriteLine("Error!");
                    }
                }
                else if (command == "Remove")
                {
                    string cardName = tokens[1];

                    if (Exist(deck, cardName))
                    {
                        deck.Remove(cardName);
                    }
                    else
                    {
                        Console.WriteLine("Card not found.");
                    }
                }
                else if (command == "Swap")
                {
                    string cardName1 = tokens[1];
                    string cardName2 = tokens[2];

                    int indexCard1 = deck.IndexOf(cardName1);
                    int indexCard2 = deck.IndexOf(cardName2);

                    string oldElement = deck[indexCard1];
                    deck[indexCard1] = deck[indexCard2];
                    deck[indexCard2] = oldElement;
                }
                else if (command == "Shuffle")
                {
                    deck.Reverse();
                }
            }

            Console.WriteLine(string.Join(' ',deck));
        }

        private static bool IsValidIndex(List<string> cards, int index)
        {
            return index >= 0 && index < cards.Count;
        }

        private static bool Exist(List<string> cards, string card)
        {
            return cards.Contains(card);
        }
    }
}