Day 11

.run/Day11 example.run.xml

@@ -0,0 +1,21 @@
+<component name="ProjectRunConfigurationManager">
+    <configuration default="false" name="Day11 example" type="DotNetProject" factoryName=".NET Project"
+                   folderName="Day11">
+        <option name="EXE_PATH" value="$PROJECT_DIR$/Day11 - Cosmic Expansion/bin/Debug/net8.0/Day11.exe"/>
+        <option name="PROGRAM_PARAMETERS" value="example.txt"/>
+        <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$/Day11 - Cosmic Expansion/bin/Debug/net8.0"/>
+        <option name="PASS_PARENT_ENVS" value="1"/>
+        <option name="USE_EXTERNAL_CONSOLE" value="0"/>
+        <option name="USE_MONO" value="0"/>
+        <option name="RUNTIME_ARGUMENTS" value=""/>
+        <option name="PROJECT_PATH" value="$PROJECT_DIR$/Day11 - Cosmic Expansion/Day11.csproj"/>
+        <option name="PROJECT_EXE_PATH_TRACKING" value="1"/>
+        <option name="PROJECT_ARGUMENTS_TRACKING" value="1"/>
+        <option name="PROJECT_WORKING_DIRECTORY_TRACKING" value="1"/>
+        <option name="PROJECT_KIND" value="DotNetCore"/>
+        <option name="PROJECT_TFM" value="net8.0"/>
+        <method v="2">
+            <option name="Build"/>
+        </method>
+    </configuration>
+</component>

.run/Day11.run.xml

@@ -0,0 +1,20 @@
+<component name="ProjectRunConfigurationManager">
+    <configuration default="false" name="Day11" type="DotNetProject" factoryName=".NET Project" folderName="Day11">
+        <option name="EXE_PATH" value="$PROJECT_DIR$/Day11 - Cosmic Expansion/bin/Debug/net8.0/Day11.exe"/>
+        <option name="PROGRAM_PARAMETERS" value=""/>
+        <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$/Day11 - Cosmic Expansion/bin/Debug/net8.0"/>
+        <option name="PASS_PARENT_ENVS" value="1"/>
+        <option name="USE_EXTERNAL_CONSOLE" value="0"/>
+        <option name="USE_MONO" value="0"/>
+        <option name="RUNTIME_ARGUMENTS" value=""/>
+        <option name="PROJECT_PATH" value="$PROJECT_DIR$/Day11 - Cosmic Expansion/Day11.csproj"/>
+        <option name="PROJECT_EXE_PATH_TRACKING" value="1"/>
+        <option name="PROJECT_ARGUMENTS_TRACKING" value="1"/>
+        <option name="PROJECT_WORKING_DIRECTORY_TRACKING" value="1"/>
+        <option name="PROJECT_KIND" value="DotNetCore"/>
+        <option name="PROJECT_TFM" value="net8.0"/>
+        <method v="2">
+            <option name="Build"/>
+        </method>
+    </configuration>
+</component>

AdventOfCode2023.sln

@@ -39,6 +39,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Day09", "Day09 - Mirage Mai
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Day10", "Day10 - Pipe Maze\Day10.csproj", "{D237B79E-9D78-4F99-B9BA-43B52609AAAE}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Day11", "Day11 - Cosmic Expansion\Day11.csproj", "{28DC51A6-39A7-4180-B890-D5B5D0AF71EC}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -92,6 +94,10 @@ Global
 		{D237B79E-9D78-4F99-B9BA-43B52609AAAE}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{D237B79E-9D78-4F99-B9BA-43B52609AAAE}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{D237B79E-9D78-4F99-B9BA-43B52609AAAE}.Release|Any CPU.Build.0 = Release|Any CPU
+		{28DC51A6-39A7-4180-B890-D5B5D0AF71EC}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{28DC51A6-39A7-4180-B890-D5B5D0AF71EC}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{28DC51A6-39A7-4180-B890-D5B5D0AF71EC}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{28DC51A6-39A7-4180-B890-D5B5D0AF71EC}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(NestedProjects) = preSolution
 		{CE8086B8-A3E4-40E0-859F-607F95D25514} = {F6C05A63-6269-425F-B877-9E9F0BC1FC26}
@@ -104,5 +110,6 @@ Global
 		{78787B01-0E1E-472E-8B58-4FFD864FC1F6} = {F6C05A63-6269-425F-B877-9E9F0BC1FC26}
 		{1E0917F9-35B3-4474-B335-E72C6BDFE667} = {F6C05A63-6269-425F-B877-9E9F0BC1FC26}
 		{D237B79E-9D78-4F99-B9BA-43B52609AAAE} = {F6C05A63-6269-425F-B877-9E9F0BC1FC26}
+		{28DC51A6-39A7-4180-B890-D5B5D0AF71EC} = {F6C05A63-6269-425F-B877-9E9F0BC1FC26}
 	EndGlobalSection
 EndGlobal

Day11 - Cosmic Expansion/.vscode/launch.json

@@ -0,0 +1,18 @@
+{
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "name": "Launch (my input)",
+      "type": "coreclr",
+      "request": "launch",
+      "preLaunchTask": "build",
+      "program": "${workspaceFolder}/bin/Debug/net8.0/Day11.dll",
+      "args": [
+        "input.txt"
+      ],
+      "cwd": "${workspaceFolder}",
+      "console": "internalConsole",
+      "stopAtEntry": false
+    }
+  ]
+}

Day11 - Cosmic Expansion/.vscode/tasks.json

@@ -0,0 +1,21 @@
+{
+  "version": "2.0.0",
+  "tasks": [
+    {
+      "label": "build",
+      "command": "dotnet",
+      "type": "process",
+      "group": {
+        "kind": "build",
+        "isDefault": true
+      },
+      "args": [
+        "build",
+        "${workspaceFolder}/Day11.csproj",
+        "/property:GenerateFullPaths=true",
+        "/consoleloggerparameters:NoSummary"
+      ],
+      "problemMatcher": "$msCompile"
+    }
+  ]
+}

Day11 - Cosmic Expansion/Day11.csproj

@@ -0,0 +1,22 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <RootNamespace>AdventOfCode.Year2023.Day11</RootNamespace>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="mMosiur.AdventOfCode.Abstractions" Version="4.4.1"/>
+    <PackageReference Include="mMosiur.AdventOfCode.Common" Version="0.1.3"/>
+  </ItemGroup>
+
+  <ItemGroup>
+    <None Update="*.txt">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+
+</Project>

Day11 - Cosmic Expansion/Day11Solver.cs

@@ -0,0 +1,63 @@
+using AdventOfCode.Abstractions;
+using AdventOfCode.Common.Geometry;
+using AdventOfCode.Year2023.Day11.Puzzle;
+
+namespace AdventOfCode.Year2023.Day11;
+
+public sealed class Day11Solver : DaySolver
+{
+	public override int Year => 2023;
+	public override int Day => 11;
+	public override string Title => "Cosmic Expansion";
+
+	private readonly IReadOnlyCollection<Point> _initialPositions;
+	private readonly Day11SolverOptions _options;
+
+	public Day11Solver(Day11SolverOptions options) : base(options)
+	{
+		_options = options;
+		var inputReader = new InputReader(options.GalaxyChar);
+		_initialPositions = inputReader.ReadGalaxyPositions(Input);
+	}
+
+	public Day11Solver(Action<Day11SolverOptions> configure)
+		: this(DaySolverOptions.FromConfigureAction(configure))
+	{
+	}
+
+	public Day11Solver() : this(new Day11SolverOptions())
+	{
+	}
+
+	public override string SolvePart1()
+	{
+		var galaxyMap = new GalaxyMap(_initialPositions);
+		galaxyMap.Expand(_options.PartOneExpansionMagnitude);
+		long sum = SumDistancesBetweenGalaxies(galaxyMap);
+		return sum.ToString();
+	}
+
+	public override string SolvePart2()
+	{
+		var galaxyMap = new GalaxyMap(_initialPositions);
+		galaxyMap.Expand(_options.PartTwoExpansionMagnitude);
+		long sum = SumDistancesBetweenGalaxies(galaxyMap);
+		return sum.ToString();
+	}
+
+	private static long SumDistancesBetweenGalaxies(GalaxyMap galaxyMap)
+	{
+		long sum = 0;
+		for (int i = 0; i < galaxyMap.Galaxies.Count; i++)
+		{
+			var g1 = galaxyMap.Galaxies[i];
+			for (int j = i + 1; j < galaxyMap.Galaxies.Count; j++)
+			{
+				var g2 = galaxyMap.Galaxies[j];
+				sum += MathG.ManhattanDistance(g1.Position, g2.Position);
+			}
+		}
+
+		return sum;
+	}
+}

Day11 - Cosmic Expansion/Day11SolverOptions.cs

@@ -0,0 +1,11 @@
+using AdventOfCode.Abstractions;
+
+namespace AdventOfCode.Year2023.Day11;
+
+public sealed class Day11SolverOptions : DaySolverOptions
+{
+	public char GalaxyChar { get; set; } = '#';
+
+	public int PartOneExpansionMagnitude { get; set; } = 2;
+	public int PartTwoExpansionMagnitude { get; set; } = 1_000_000;
+}

Day11 - Cosmic Expansion/GlobalUsings.cs

@@ -0,0 +1 @@
+global using Point = AdventOfCode.Common.Geometry.Point2D<long>;

Day11 - Cosmic Expansion/Program.cs

@@ -0,0 +1,42 @@
+using System.Diagnostics;
+using AdventOfCode;
+using AdventOfCode.Year2023.Day11;
+
+try
+{
+	string? filepath = args.Length switch
+	{
+		0 => null,
+		1 => args[0],
+		_ => throw new CommandLineException(
+			$"Program was called with too many arguments. Proper usage: \"dotnet run [<input filepath>]\"."
+		)
+	};
+
+	Day11Solver solver = new(options => { options.InputFilepath = filepath ?? options.InputFilepath; });
+
+	Console.WriteLine($"--- Day {solver.Day}: {solver.Title} ---");
+
+	Console.Write("Part one: ");
+	string part1 = solver.SolvePart1();
+	Console.WriteLine(part1);
+
+	Console.Write("Part two: ");
+	string part2 = solver.SolvePart2();
+	Console.WriteLine(part2);
+}
+catch (AdventOfCodeException e)
+{
+	string errorPrefix = e switch
+	{
+		CommandLineException => "Command line error",
+		InputException => "Input error",
+		DaySolverException => "Day solver error",
+		_ => throw new UnreachableException($"Unknown exception type \"{e.GetType()}\".")
+	};
+
+	Console.ForegroundColor = ConsoleColor.Red;
+	Console.Error.WriteLine($"{errorPrefix}: {e.Message}");
+	Console.ResetColor();
+	Environment.Exit(1);
+}

Day11 - Cosmic Expansion/Puzzle/Galaxy.cs

@@ -0,0 +1,11 @@
+namespace AdventOfCode.Year2023.Day11.Puzzle;
+
+internal interface IGalaxy
+{
+	Point Position { get; }
+}
+
+internal sealed class Galaxy(Point position) : IGalaxy
+{
+	public Point Position { get; set; } = position;
+}

Day11 - Cosmic Expansion/Puzzle/GalaxyMap.cs

@@ -0,0 +1,95 @@
+namespace AdventOfCode.Year2023.Day11.Puzzle;
+
+internal sealed class GalaxyMap
+{
+	private const int ExpandListInitialCapacity = 10;
+
+	private readonly List<Galaxy> _galaxies;
+	private long _maxColumn;
+	private long _maxRow;
+
+	public GalaxyMap(IEnumerable<Point> galaxyPositions)
+	{
+		_galaxies = galaxyPositions.Select(p => new Galaxy(p)).ToList();
+		_maxRow = _galaxies.Max(g => g.Position.X);
+		_maxColumn = _galaxies.Max(g => g.Position.Y);
+	}
+
+	public IReadOnlyList<IGalaxy> Galaxies => _galaxies;
+
+	public void Expand(int expansionMagnitude)
+	{
+		ExpandRows(expansionMagnitude);
+		ExpandColumns(expansionMagnitude);
+	}
+
+	private void ExpandRows(int expansionMagnitude)
+	{
+		var galaxiesPerRow = new List<Galaxy>?[_maxRow + 1];
+		foreach (var galaxy in _galaxies)
+		{
+			long row = galaxy.Position.X;
+			var rowList = galaxiesPerRow[row];
+			if (rowList is null)
+			{
+				rowList = new List<Galaxy>(ExpandListInitialCapacity);
+				galaxiesPerRow[row] = rowList;
+			}
+
+			rowList.Add(galaxy);
+		}
+
+		int rowOffset = 0;
+		for (int row = 0; row <= _maxRow; row++)
+		{
+			var rowList = galaxiesPerRow[row];
+			if (rowList is null)
+			{
+				rowOffset = rowOffset + expansionMagnitude - 1;
+				continue;
+			}
+
+			foreach (var galaxy in rowList)
+			{
+				galaxy.Position = new(row + rowOffset, galaxy.Position.Y);
+			}
+		}
+
+		_maxRow += rowOffset;
+	}
+
+	private void ExpandColumns(int expansionMagnitude)
+	{
+		var galaxiesPerColumn = new List<Galaxy>?[_maxColumn + 1];
+		foreach (var galaxy in _galaxies)
+		{
+			long column = galaxy.Position.Y;
+			var columnList = galaxiesPerColumn[column];
+			if (columnList is null)
+			{
+				columnList = new List<Galaxy>(ExpandListInitialCapacity);
+				galaxiesPerColumn[column] = columnList;
+			}
+
+			columnList.Add(galaxy);
+		}
+
+		int columnOffset = 0;
+		for (int column = 0; column <= _maxColumn; column++)
+		{
+			var columnList = galaxiesPerColumn[column];
+			if (columnList is null)
+			{
+				columnOffset = columnOffset + expansionMagnitude - 1;
+				continue;
+			}
+
+			foreach (var galaxy in columnList)
+			{
+				galaxy.Position = new(galaxy.Position.X, column + columnOffset);
+			}
+		}
+
+		_maxColumn += columnOffset;
+	}
+}

Day11 - Cosmic Expansion/Puzzle/InputReader.cs

@@ -0,0 +1,35 @@
+namespace AdventOfCode.Year2023.Day11.Puzzle;
+
+internal sealed class InputReader
+{
+	private const int InitialGalaxyListSize = 500;
+	private readonly char _galaxyChar;
+
+	public InputReader(char galaxyChar)
+	{
+		_galaxyChar = galaxyChar;
+	}
+
+	public IReadOnlyCollection<Point> ReadGalaxyPositions(string input)
+	{
+		var list = new List<Point>(InitialGalaxyListSize);
+		int row = 0;
+		foreach (var lineSpan in input.AsSpan().EnumerateLines())
+		{
+			int column = 0;
+			foreach (char c in lineSpan)
+			{
+				if (c == _galaxyChar)
+				{
+					list.Add(new(row, column));
+				}
+
+				column++;
+			}
+
+			row++;
+		}
+
+		return list;
+	}
+}