Prog. Fundamentals Exam Prep III - 02. Command Interpreter

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Numerics;
using System.Text.RegularExpressions;

namespace _14_ExamPreparation3
{
    class Program
    {
      static void Main(string[] args)
        {
            string[] array = Console.ReadLine()
                .Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);

            while (true)
            {
                string line = Console.ReadLine();
                if (line == "end")
                {
                    break;
                }
                string[] commandParts = line.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
                switch (commandParts[0])
                {
                    case "reverse":
                        array = ReverseArrayPart(array, int.Parse(commandParts[2]), int.Parse(commandParts.Last()));
                        break;
                    case "sort":
                        array = SortArrayPart(array, int.Parse(commandParts[2]), int.Parse(commandParts.Last()));
                        break;
                    case "rollLeft":
                        if (int.Parse(commandParts[1]) < 0)
                        {
                            Console.WriteLine("Invalid input parameters.");
                            break;
                        }
                        array = Roll(array, int.Parse(commandParts[1]), "left");
                        break;
                    case "rollRight":
                        if (int.Parse(commandParts[1]) < 0)
                        {
                            Console.WriteLine("Invalid input parameters.");
                            break;
                        }
                        array = Roll(array, int.Parse(commandParts[1]), "right");
                        break;
                }
            }
            Console.WriteLine($"[{string.Join(", ", array)}]");
        }

        static string[] Roll(string[] array, int count, string side)
        {
            List<string> list = array.ToList();
            if (side == "left")
            {
                for (int i = 0; i < count; i++)
                {
                    string firsElement = list[0];
                    list.RemoveAt(0);
                    list.Insert(list.Count, firsElement);
                }
            }
            if (side == "right")
            {
                for (int i = 0; i < count; i++)
                {
                    string LastElement = list[list.Count - 1];
                    list.RemoveAt(list.Count - 1);
                    list.Insert(0, LastElement);
                }
            }
            array = list.ToArray();
            list.Clear();
            return array;
        }

        static string[] ReverseArrayPart(string[] array, int start, int count)
        {
            if (start < 0 || start >= array.Length)
            {
                Console.WriteLine("Invalid input parameters.");
                return array;
            }
            if (start + count < 0 || count < 0 || start + count - 1>= array.Length)
            {
                Console.WriteLine("Invalid input parameters.");
                return array;
            }
            string[] firstPart = array.Take(start).ToArray();
            string[] reversedPart = array.Skip(start).Take(count).Reverse().ToArray();
            string[] lastPart = array.Skip(start + count).ToArray();
            return firstPart.Concat(reversedPart).Concat(lastPart).ToArray();
        }

        static string[] SortArrayPart(string[] array, int start, int count)
        {
            if (start < 0 || start >= array.Length)
            {
                Console.WriteLine("Invalid input parameters.");
                return array;
            }
            if (start + count < 0 || count < 0 || start + count - 1>= array.Length)
            {
                Console.WriteLine("Invalid input parameters.");
                return array;
            }
            string[] firstPart = array.Take(start).ToArray();
            string[] sortedPart = array.Skip(start).Take(count).OrderBy(s => s).ToArray();
            string[] lastPart = array.Skip(start + count).ToArray();
            return firstPart.Concat(sortedPart).Concat(lastPart).ToArray();
        }
    }
}