Advent of Code - Day 3 Part 1

Program.cs

namespace Day3Part1 {

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

	public static class Extensions {

		public static void DeliverPresent(this Dictionary<Tuple<int, int>, int> houses, Tuple<int, int> house) {
			if (houses.ContainsKey(house))
				houses[house] += 1;
			else
				houses[house] = 1;
		}

		public static Tuple<int, int> GoRight(this Tuple<int, int> currentHouse) {
			return new Tuple<int, int>(currentHouse.Item1 + 1, currentHouse.Item2);
		}

		public static Tuple<int, int> GoLeft(this Tuple<int, int> currentHouse) {
			return new Tuple<int, int>(currentHouse.Item1 - 1, currentHouse.Item2);
		}

		public static Tuple<int, int> GoUp(this Tuple<int, int> currentHouse) {
			return new Tuple<int, int>(currentHouse.Item1, currentHouse.Item2 + 1);
		}

		public static Tuple<int, int> GoDown(this Tuple<int, int> currentHouse) {
			return new Tuple<int, int>(currentHouse.Item1, currentHouse.Item2 - 1);
		}

	}

	public class Program {

		public static void Main(string[] args) {

			Dictionary<Tuple<int, int>, int> houses = new Dictionary<Tuple<int,int>, int>();
			string input = File.ReadAllText("Input.txt");

			Tuple<int, int> currentHouse = new Tuple<int, int>(0, 0);
			// For some reason, we deliver to where we're at.  So do that.
			houses.DeliverPresent(currentHouse);

			foreach(char instruction in input) {

				if (instruction == '<')
					currentHouse = currentHouse.GoLeft();
				else if (instruction == '>')
					currentHouse = currentHouse.GoRight();
				else if (instruction == '^')
					currentHouse = currentHouse.GoUp();
				else if (instruction == 'v')
					currentHouse = currentHouse.GoDown();

				houses.DeliverPresent(currentHouse);

			}

			Console.WriteLine($"{houses.Count()} houses got presents!");

			Console.ReadKey();

		}

	}

}