Adv2018/D20.1/Program.cs

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

namespace D20._1
{
    class Program
    {
        static (int x, int y) MoveTo(char c, (int x, int y) pos)
        {
            switch (c)
            {
                case 'N': pos.y -= 1; break;
                case 'S': pos.y += 1; break;
                case 'W': pos.x -= 1; break;
                case 'E': pos.x += 1; break;
            }

            return pos;
        }

        static Dictionary<(int x, int y), int> makeMap(string input)
        {
            var result = new Dictionary<(int x, int y), int>();
            var nodes = new Stack<((int x, int y), int dist)>();
            ((int x, int y) pos, int dist) cur = ((0, 0), 0);

            foreach (var c in input)
            {
                switch (c)
                {
                    case 'N':
                    case 'S':
                    case 'E':
                    case 'W':
                        cur.pos = MoveTo(c, cur.pos);
                        cur.dist++;
                        result.TryAdd(cur.pos, cur.dist);
                        break;
                    case '(':
                        nodes.Push(cur);
                        break;
                    case '|':
                        cur = nodes.Peek();
                        break;
                    case ')':
                        cur = nodes.Pop();
                        break;
                }
            }
            return result;
        }

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

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

            //regex = @"^ENNWSWW(NEWS|)SSSEEN(WNSE|)EE(SWEN|)NNN$";
            //regex = @"^WSSEESWWWNW(S|NENNEEEENN(ESSSSW(NWSW|SSEN)|WSWWN(E|WWS(E|SS))))$";
            //regex = @"^N(EEENWWW|N)$";

            regex = regex.TrimStart('^').TrimEnd('$');

            var map = makeMap(regex);

            int max = map.Max(p => p.Value);
            int d = map.Count(p => p.Value >= 1000);
            Console.WriteLine($"Ex 1 : {max}\nEx 2 ; {d}");
        }
    }
}