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

public class Day3
{

    static void PartA()
    {
        // Day 3 !
        string path = Directory.GetCurrentDirectory() + "/input.txt";
        char[,] map = new char[31, 323];
        int trees = 0;
        using (StreamReader sr = new StreamReader(path))
        {
            for (int y = 0; y < 323; y++)
            {
                string line = sr.ReadLine();
                for (int x = 0; x < 31; x++)
                {
                    map[x, y] = line[x];
                }
            }
        }
        int _x = 0, _y = 0;
        while (_y < 323)
        {
            if (map[_x, _y] == '#')
            {
                trees++;
                map[_x, _y] = 'X';
            }
            else map[_x, _y] = 'O';
            _y++;
            _x = (_x + 3) % 31;
        }
        for (int y = 0; y < 323; y++)
        {
            for (int x = 0; x < 31; x++)
            {
                Console.Write(map[x, y]);
            }
            Console.WriteLine();
        }
        Console.WriteLine(trees);
    }

    static void PartB()
    {
        // Day 3 !
        string path = Directory.GetCurrentDirectory() + "/input.txt";
        char[,] map = new char[31, 323];
        int trees = 0;
        using (StreamReader sr = new StreamReader(path))
        {
            for (int y = 0; y < 323; y++)
            {
                string line = sr.ReadLine();
                for (int x = 0; x < 31; x++)
                {
                    map[x, y] = line[x];
                }
            }
        }
        int _x = 0, _y = 0;
        long total = 1;
        Tuple<int, int>[] slopes =
        {
                 Tuple.Create(1, 1),
                 Tuple.Create(3, 1),
                 Tuple.Create(5, 1),
                 Tuple.Create(7, 1),
                 Tuple.Create(1, 2),
            };

        foreach (Tuple<int, int> slope in slopes)
        {
            while (_y < 323)
            {
                if (map[_x, _y] == '#')
                {
                    trees++;
                }
                _y += slope.Item2;
                _x = (_x + slope.Item1) % 31;
            }
            total *= trees;
            trees = 0;
            _x = 0;
            _y = 0;
        }
        Console.WriteLine(total);
    }
}