Adv2018/D2.1/Program.cs

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

namespace D2._1
{
    class Program
    {
        static void Main(string[] args)
        {
            if (args.Length < 1) return;
            if (File.Exists(args[0]) == false) return;

            var file = File.OpenText(args[0]);

            int numberOfTwos = 0, numberOfThrees = 0;

            do
            {
                var line = file.ReadLine();
                if (line == null) break;

                var letter = new Dictionary<char, int>();

                foreach (var car in line)
                {
                    if (letter.ContainsKey(car)) letter[car]++;
                    else letter.Add(car, 1);
                }

                if (letter.Any(l => l.Value == 2)) numberOfTwos++;
                if (letter.Any(l => l.Value == 3)) numberOfThrees++;

            } while (true);

            Console.WriteLine($"Result : {numberOfTwos * numberOfThrees}");
        }
    }
}