CryptoBlockchainEdited

using System;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

namespace _03.Problem
{
    public class ProblemThree
    {
        public static void Main()
        {

                int n = int.Parse(Console.ReadLine());
                StringBuilder cryptoBlockChain = new StringBuilder();

                for (int i = 0; i < n; i++)
                {
                    string currentCryptoBlock = Console.ReadLine();
                    cryptoBlockChain.Append(currentCryptoBlock);
                }

            var pattern = @"\[([^\d\[\]\{\}]*)([\d]{3,})([^\[\]\{\}]*)\]|\{([^\d\[\]\{\}]*)([\d]{3,})([^\[\]\{\}]*)\}";
            Regex regex = new Regex(pattern);

            MatchCollection matches = regex.Matches(cryptoBlockChain.ToString());

            StringBuilder result = new StringBuilder();

                foreach (Match match in matches)
                {
                    if (match.ToString().StartsWith("{"))
                    {
                        int length = match.ToString().Length;
                        string digits = match.Groups[5].Value.ToString();
                        ParseNumbers(result, length, digits);
                    }
                    else if (match.ToString().StartsWith("["))
                    {
                        int length = match.ToString().Length;
                        string digits = match.Groups[2].Value.ToString();
                        ParseNumbers(result, length, digits);
                    }
                }

                Console.WriteLine(result.ToString());
            }

            public static void ParseNumbers(StringBuilder result, int length, string digits)
            {
                if (digits.Length % 3 == 0)
                {
                    while (digits.Length > 0)
                    {
                        string currentNumberAsString = new string(digits.Take(3).ToArray());
                        StringBuilder sb = new StringBuilder(digits);
                        sb.Remove(0, 3);
                        digits = sb.ToString();
                        int numberAsInt = int.Parse(currentNumberAsString);
                        int charToAdd = numberAsInt - length;
                        result.Append((char)charToAdd);
                    }
                }
            }



            // my solution to compare:

            //    int n = int.Parse(Console.ReadLine());
            //    var sticked = new StringBuilder();
            //    var output = new StringBuilder();

            //    for (int i = 0; i < n; i++)
            //    {
            //        sticked.Append(Console.ReadLine());
            //    }

            //    var pattern = @"\[([^\d\[\]\{\}]*)(?<numbers>[\d]{3,})([^\[\]\{\}]*)\]|\{([^\d\[\]\{\}]*)(?<numbers>[\d]{3,})([^\[\]\{\}]*)\}";
            //    Regex regex = new Regex(pattern);

            //    MatchCollection cryptoBlocks = regex.Matches(sticked.ToString());

            //    for (int i = 0; i < cryptoBlocks.Count; i++)
            //    {
            //        if (cryptoBlocks[i].Groups["numbers"].Value.Length % 3 != 0)
            //        {
            //            continue;
            //        }

            //        var currentBlock = cryptoBlocks[i].Groups["numbers"].Value;
            //        var numbersLength = cryptoBlocks[i].Groups["numbers"].Value.Length;
            //        var totalLength = cryptoBlocks[i].Length;

            //        while (currentBlock.Length > 0)
            //        {
            //            var currentChar = currentBlock.Substring(0, 3);
            //            output.Append((char)(int.Parse(currentChar) - totalLength));
            //            currentBlock = currentBlock.Substring(3);
            //        }
            //    }

            //    Console.WriteLine(output);
            //}
        }
}