Adv2015/D25.1/Program.cs

using System;
using System.IO;
using System.Text.RegularExpressions;

namespace D25._1
{
    class Program
    {
        static void Main(string[] args)
        {
            if (args.Length < 1) throw new ArgumentException();
            if (File.Exists(args[0]) == false) throw new FileNotFoundException();

            int row = 1, col = 1;
            ulong n = 20151125;

            var regex = new Regex(@"row (?<r>\d+), column (?<c>\d+)");
            string input = File.ReadAllText(args[0]);
            var result = regex.Match(input);

            var breakRow = int.Parse(result.Groups["r"].Value);
            var breakColumn = int.Parse(result.Groups["c"].Value);

            while (true)
            {
                row--;
                col++;

                if (row == 0)
                {
                    row = col;
                    col = 1;
                }

                n = (n * 252533) % 33554393;

                if (row == breakRow && col == breakColumn)
                    break;
            }

            Console.WriteLine($"Answer is : {n}");
        }
    }
}