Adv2015/D03.1/Program.cs

using System;
using System.Collections.Generic;
using System.IO;

namespace D03._1
{
    class Program
    {
        static void Main(string[] args)
        {
            if (args.Length < 1) throw new ArgumentException();
            if (File.Exists(args[0]) == false) throw new FileNotFoundException();
            
            string text = "";
            using (var file = File.OpenText(args[0]))
            {
                text = file.ReadToEnd();
            }

            (int x, int y) pos = (0, 0);
            var visited = new HashSet<(int, int)>
            {
                pos
            };

            foreach (var c in text)
            {
                switch (c)
                {
                    case '>': pos.x++; break;
                    case '<': pos.x--; break;
                    case '^': pos.y--; break;
                    case 'v': case 'V': pos.y++; break;
                    default: continue;
                }
                visited.Add(pos);
            }

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