CommandInterpreter

namespace CommandInterpreter
{
    using System;
    using System.Collections.Generic;
    using System.Linq;

    public class CommandInterpreter
    {
        public static void Main()
        {
            List<string> collection = Console.ReadLine()
                .Split(new[] { ' ', '\t'}, StringSplitOptions.RemoveEmptyEntries)
                .ToList();

            string command = Console.ReadLine();

            while (command != "end")
            {
                string[] commandArguments = command.Split(' '); ;

                switch (commandArguments[0])
                {
                    case "reverse":
                        ExecuteReverseCommand(collection, commandArguments);
                        break;
                    case "sort":
                        ExecuteSortCommand(collection, commandArguments);
                        break;
                    case "rollLeft":
                        ExecuteRollLeftCommand(collection, commandArguments);
                        break;
                    case "rollRight":
                        ExecuteRollRightComamnd(collection, commandArguments);
                        break;
                }

                command = Console.ReadLine();
            }

            Console.WriteLine("[{0}]", string.Join(", ", collection));
        }

        private static void ExecuteRollRightComamnd(List<string> collection, string[] commandArguments)
        {
            int count = int.Parse(commandArguments[1]) % collection.Count;

            if (count < 0)
            {
                Console.WriteLine("Invalid input parameters.");
                return;
            }

            for (int i = 0; i < count; i++)
            {
                string lastElement = collection[collection.Count-1];
                collection.RemoveAt(collection.Count - 1);
                collection.Insert(0, lastElement);
            }
        }

        private static void ExecuteRollLeftCommand(List<string> collection, string[] commandArguments)
        {
            int count = int.Parse(commandArguments[1]) % collection.Count;

            if (count < 0)
            {
                Console.WriteLine("Invalid input parameters.");
                return;
            }

            for (int i = 0; i < count; i++)
            {
                string fisrtElement = collection[0];
                collection.Remove(fisrtElement);
                collection.Add(fisrtElement);
            }
        }

        private static void ExecuteSortCommand(List<string> collection, string[] commandArguments)
        {
            int start = int.Parse(commandArguments[2]);
            int count = int.Parse(commandArguments[4]);

            if (start < 0 || start >= collection.Count || count < 0 || start + count > collection.Count)
            {
                Console.WriteLine("Invalid input parameters.");
                return;
            }

            collection.Sort(start, count, StringComparer.InvariantCulture);
        }

        private static void ExecuteReverseCommand(List<string> collection, string[] commandArguments)
        {
            int start = int.Parse(commandArguments[2]);
            int count = int.Parse(commandArguments[4]);

            if (start < 0 || start >= collection.Count || count < 0 || start + count > collection.Count)
            {
                Console.WriteLine("Invalid input parameters.");
                return;
            }

            collection.Reverse(start, count);
        }
    }
}

// Example for input:
//1 2 5 8 7 3 10 6 4 9
//reverse from 2 count 4
//end