02. Treasure Hunt

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

namespace TreasureHunt
{
    class Program
    {
        static void Main(string[] args)
        {
            var chest = Console.ReadLine().Split('|').ToList();
            string command;

            while ((command = Console.ReadLine()) != "Yohoho!")
            {
                var tokens = command.Split(' ').ToList();
                command = tokens[0];
                if (command == "Loot")
                {
                    for (int i = 1; i < tokens.Count; i++)
                    {
                        if (!chest.Contains(tokens[i]))
                        {
                            chest.Insert(0, tokens[i]);
                        }
                    }
                }
                else if (command == "Drop")
                {
                    int index = int.Parse(tokens[1]);
                    if (index >= 0 && index < chest.Count)
                    {
                        chest.Add(chest[index]);
                        chest.RemoveAt(index);
                    }
                }
                else if (command == "Steal")
                {
                    int count = int.Parse(tokens[1]);
                    if (count >= chest.Count)
                    {
                        count = chest.Count;
                    }
                    Console.WriteLine(String.Join(", ", chest.GetRange(chest.Count - count, count)));
                    chest.RemoveRange(chest.Count - count, count);
                }
            }

            if (chest.Count == 0)
            {
                Console.WriteLine("Failed treasure hunt.");
            }
            else
            {
                double averageGain = (double)String.Join("", chest).Length / chest.Count;
                Console.WriteLine($"Average treasure gain: {averageGain:f2} pirate credits.");
            }
        }
    }
}