CommandInterpreter

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

namespace CommandInterpreter

{
    class Program
    {
        static void Main(string[] args)
        {
            List<string> seq = Console.ReadLine().Split(" ", StringSplitOptions.RemoveEmptyEntries).ToList();
            while (true)
            {
                var command = Console.ReadLine();
                if (command == "end")
                {
                    break;
                }

                string[] commands = command.Split();
                string instruction = commands[0];
                long start = 0;
                long count = 0;
                if (instruction == "reverse" || instruction == "sort")
                {
                    start = long.Parse(commands[2]);
                    count = long.Parse(commands[4]);
                    if (start < 0 || start + count > seq.Count || count < 0 || start > seq.Count - 1)
                    {
                        Console.WriteLine("Invalid input parameters.");
                    }
                    else
                    {
                        seq = Reverse(seq, start, count, instruction);
                    }
                }
            }
            Console.WriteLine($"[{String.Join(", ", seq)}]");
        }

        private static List<string> Reverse(List<string> seq, long start, long count, string instruction)
        {
            List<string> leftPart = seq.Take((int)start).ToList();
            List<string> rightPart = seq.Skip((int)(start + count)).ToList();
            List<string> toTreat = seq.Skip((int)start).Take((int)count).ToList();

            if (instruction == "reverse")
            {
                toTreat.Reverse();

            }
            else if (instruction == "sort")
            {
                toTreat.Sort();
            }
            List<string> treated = new List<string>();
            treated.AddRange(leftPart);
            treated.AddRange(toTreat);
            treated.AddRange(rightPart);

            return treated;

        }
    }
}