Day 11

AdventOfCode/AdventOfCode.csproj

@@ -43,6 +43,8 @@
 	<None Remove="Problems\AOC2022\Day9\test2.txt" />
 	<None Remove="problems\aoc2023\day10\input.txt" />
 	<None Remove="problems\aoc2023\day10\sample.txt" />
+	<None Remove="problems\aoc2023\day11\input.txt" />
+	<None Remove="problems\aoc2023\day11\sample.txt" />
 	<None Remove="problems\aoc2023\day1\input.txt" />
 	<None Remove="problems\aoc2023\day2\input.txt" />
 	<None Remove="problems\aoc2023\day3\input.txt" />

AdventOfCode/Problems/AOC2023/Day11/CosmicExpansion.cs

@@ -0,0 +1,89 @@
+using AdventOfCode.Runner.Attributes;
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace AdventOfCode.Problems.AOC2023.Day11;
+
+[ProblemInfo(2023, 11, "Cosmic Expansion")]
+internal class CosmicExpansion : Problem<int, long>
+{
+	private string[] _data = [];
+	private int[] _yGaps = [];
+	private int[] _xGaps = [];
+
+	public override void CalculatePart1()
+	{
+		var points = GetPoints().Select(p => Inflate(p, 2)).ToList();
+		for (int i = 0; i < points.Count - 1; i++)
+		{
+			for (int j = i + 1; j < points.Count; j++)
+			{
+				var a = points[i];
+				var b = points[j];
+				Part1 += GetDistance(a, b);
+			}
+		}
+	}
+
+	public List<(int x, int y)> GetPoints()
+	{
+		var result = new List<(int x, int y)>();
+		for (int y = 0; y < _data.Length; y++)
+		{
+			for (int x = 0; x < _data[0].Length; x++)
+			{
+				if (_data[y][x] == '#')
+					result.Add((x, y));
+			}
+		}
+		return result;
+	}
+
+	public int GetDistance((int x, int y) a, (int x, int y) b)
+	{
+		var xDist = Math.Abs(a.x - b.x);
+		var yDist = Math.Abs(a.y - b.y);
+
+		return xDist + yDist;
+	}
+
+	public (int x, int y) Inflate((int x, int y) point, int factor)
+	{
+		factor -= 1;
+		var cX = _xGaps.Count(x => point.x >= x); 
+		var cY = _yGaps.Count(y => point.y >= y);
+		return (point.x + cX * factor, point.y + cY * factor);
+	}
+
+	public override void CalculatePart2()
+	{
+		var points = GetPoints().Select(p => Inflate(p, 1000000)).ToList();
+		for (int i = 0; i < points.Count - 1; i++)
+		{
+			for (int j = i + 1; j < points.Count; j++)
+			{
+				var a = points[i];
+				var b = points[j];
+				Part2 += GetDistance(a, b);
+			}
+		}
+	}
+
+	public override void LoadInput()
+	{
+		_data = ReadInputLines();
+		_yGaps = _data.Select((v, i) => (c: v.Count(x => x == '.'), i))
+					.Where(v => v.c == _data[0].Length)
+					.Select(v => v.i)
+					.ToArray();
+
+		_xGaps = _data.Transpose().Select((v, i) => (c: v.Count(x => x == '.'), i))
+					.Where(v => v.c == _data[0].Length)
+					.Select(v => v.i)
+					.ToArray();
+	}
+}

AdventOfCode/Runner/Extensions.cs

@@ -27,4 +27,37 @@ public static class Extensions
 		}
 		return a;
 	}
+
+	public static IEnumerable<IEnumerable<T2>> Transpose<T, T2>(this IEnumerable<T> data) where T: IEnumerable<T2>
+	{
+		var range = Enumerable.Range(0, data.First().Count());
+
+		return range.Select(i => data.Select(l => l.Skip(i).First()));
+	}
+
+	public static IEnumerable<T> Transpose<T, T2>(this IEnumerable<T> data, Func<IEnumerable<T2>, T> formatter) where T : IEnumerable<T2>
+	{
+		var range = Enumerable.Range(0, data.First().Count());
+
+		return range.Select(i => formatter(data.Select(l => l.Skip(i).First())));
+	}
+
+	public static IEnumerable<string> Transpose(this IEnumerable<string> data)
+	{
+		return Transpose<string, char>(data, a => string.Join("", a));
+	}
+
+	public static IEnumerable<List<T>> Permute<T>(this IEnumerable<T> values)
+	{
+		IEnumerable<List<T>> permutate(IEnumerable<T> reminder, IEnumerable<T> prefix)
+		{
+			return !reminder.Any()
+				? new List<List<T>> { prefix.ToList() }
+				: reminder.SelectMany((c, i) => permutate(
+					reminder.Take(i).Concat(reminder.Skip(i + 1)).ToList(),
+					prefix.Append(c)));
+		}
+		return permutate(values, Enumerable.Empty<T>());
+	}
+
 }