aoc/AdventOfCode/TwentyTwenty/Three.cs

using AdventOfCode.Contracts;
using System;

namespace AoC.TwentyTwenty
{
    namespace AoC.TwentyTwenty
    {
        class Three : Day
        {
            public override int Year => 2020;
            public override int DayNumber => 3;

            public override void BigBoi(string[] input)
            {
                throw new NotImplementedException();
            }

            public override void Part1(string[] input)
            {
                Print("1", Numbers(input, 1, 3));
            }

            public override void Part2(string[] input)
            {
                var thing =
                Numbers(input, 1, 1) *
                Numbers(input, 1, 3) *
                Numbers(input, 1, 5) *
                Numbers(input, 1, 7) *
                Numbers(input, 2, 1);

                Print("2", thing);
            }

            public static long Numbers(string[] input, int rows, int columns)
            {
                int cursor = 0;
                long trees = 0;

                for (int i = 0; i < input.Length; i += rows)
                {
                    if (input[i][cursor % input[i].Length] == '#')
                    {
                        trees += 1;
                    }

                    cursor += columns;
                }

                return trees;
            }
        }
    }
}