CubicWithRegex

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

namespace _04_CubicwithRegex
{
    class Program
    {
        static void Main(string[] args)
        {
            var pattrern = @"(\d+)([a-zA-Z]+)(\W|[0-9]+)";
            var regex = new Regex(pattrern);

            while (true)
            {
                var input = Console.ReadLine();
                if (input == "Over!")
                {
                    break;
                }
                var number = int.Parse(Console.ReadLine());

                var matches = regex.Match(input);

                if (matches.Length != input.Length)
                {
                    continue;
                }

                var firstMatch = matches.Groups[1].Value;
                var text = matches.Groups[2].Value;
                var lastMatch = matches.Groups[3].Value;

                var digits = "";
                foreach (var character in firstMatch)
                {
                    var num = int.Parse(character.ToString());
                    digits += num;
                }
                foreach (var character in lastMatch)
                {
                    var num = -1;
                    if (int.TryParse(character.ToString(), out num))
                    {
                        digits += num;
                    }
                }
                var verificationCode = "";
                foreach (var index in digits)
                {
                    var digit = int.Parse(index.ToString());
                    if (digit < text.Length)
                    {
                        verificationCode += text[digit];
                    }
                    else
                    {
                        verificationCode += " ";
                    }
                }
                Console.WriteLine($"{text} == {verificationCode}");
            }
        }
    }
}