Day 17

AdventOfCode.sln

@@ -69,6 +69,10 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Day16_1", "Day16_1\Day16_1.
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Day16_2", "Day16_2\Day16_2.csproj", "{CEC9381F-43E1-42A3-8D87-5D44309B67A2}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Day17_1", "Day17_1\Day17_1.csproj", "{84BC1C44-6E4B-4860-A92E-8E31D6DFBB94}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Day17_2", "Day17_2\Day17_2.csproj", "{BD5D483C-4BA9-4A28-9551-A4ACBE6F541C}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -207,6 +211,14 @@ Global
 		{CEC9381F-43E1-42A3-8D87-5D44309B67A2}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{CEC9381F-43E1-42A3-8D87-5D44309B67A2}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{CEC9381F-43E1-42A3-8D87-5D44309B67A2}.Release|Any CPU.Build.0 = Release|Any CPU
+		{84BC1C44-6E4B-4860-A92E-8E31D6DFBB94}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{84BC1C44-6E4B-4860-A92E-8E31D6DFBB94}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{84BC1C44-6E4B-4860-A92E-8E31D6DFBB94}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{84BC1C44-6E4B-4860-A92E-8E31D6DFBB94}.Release|Any CPU.Build.0 = Release|Any CPU
+		{BD5D483C-4BA9-4A28-9551-A4ACBE6F541C}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{BD5D483C-4BA9-4A28-9551-A4ACBE6F541C}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{BD5D483C-4BA9-4A28-9551-A4ACBE6F541C}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{BD5D483C-4BA9-4A28-9551-A4ACBE6F541C}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

Day17_1/Day17_1.csproj

@@ -0,0 +1,24 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <None Remove="input.txt" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Content Include="input.txt">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Tools\Tools.csproj" />
+  </ItemGroup>
+
+</Project>

Day17_1/Program.cs

@@ -0,0 +1,70 @@
+using Tools;
+
+var input = File.ReadAllLines("input.txt");
+var width = input[0].Length;
+var height = input.Length;
+var map = new int[width, height];
+
+for (int y = 0; y < height; y++)
+{
+    for (int x = 0; x < width; x++)
+    {
+        map[x, y] = input[y][x] - '0';
+    }
+}
+
+var visited = new HashSet<Node>();
+var minDistances = new Dictionary<Node, int>();
+minDistances[new Node((0, 0), (0, 1), 0)] = 0;
+minDistances[new Node((0, 0), (1, 0), 0)] = 0;
+while (true)
+{
+    var minNode = minDistances.OrderBy(x => x.Value).FirstOrDefault();
+    minDistances.Remove(minNode.Key);
+    visited.Add(minNode.Key);
+    var currentNode = minNode.Key;
+    var totalHeat = minNode.Value;
+    var direction = currentNode.Direction;
+    var position = currentNode.Position;
+    var directionSteps = currentNode.DirectionSteps;
+
+    if (currentNode.Position == (width - 1, height - 1))
+    {
+        Console.WriteLine(totalHeat);
+        break;
+    }
+
+    if (directionSteps < 3)
+    {
+        TryNextNode(direction, directionSteps + 1);
+    }
+
+    var leftTurn = (direction.Y, -direction.X);
+    TryNextNode(leftTurn, 1);
+    var rightTurn = (-direction.Y, direction.X);
+    TryNextNode(rightTurn, 1);
+
+    void TryNextNode(Point direction, int steps)
+    {
+        var nextPosition = new Point(position.X + direction.X, position.Y + direction.Y);
+        if (nextPosition.X < 0 || nextPosition.X >= width || nextPosition.Y < 0 || nextPosition.Y >= height)
+        {
+            return;
+        }
+
+        int nextHeat = totalHeat + map[nextPosition.X, nextPosition.Y];
+        var nextNode = new Node(nextPosition, direction, steps);
+
+        if (visited.Contains(nextNode))
+        {
+            return;
+        }
+
+        if (!minDistances.ContainsKey(nextNode) || minDistances[nextNode] > nextHeat)
+        {
+            minDistances[nextNode] = nextHeat;
+        }
+    }
+}
+
+record Node(Point Position, Point Direction, int DirectionSteps);

Day17_1/Properties/launchSettings.json

@@ -0,0 +1,7 @@
+{
+  "profiles": {
+    "Run": {
+      "commandName": "Project"
+    }
+  }
+}

Day17_1/input.txt

@@ -0,0 +1,5 @@
+111111111111
+999999999991
+999999999991
+999999999991
+999999999991

Day17_2/Day17_2.csproj

@@ -0,0 +1,24 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <None Remove="input.txt" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Content Include="input.txt">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Tools\Tools.csproj" />
+  </ItemGroup>
+
+</Project>

Day17_2/Program.cs

@@ -0,0 +1,76 @@
+using Tools;
+
+const int MinDirectionSteps = 4;
+const int MaxDirectionSteps = 10;
+
+var input = File.ReadAllLines("input.txt");
+var width = input[0].Length;
+var height = input.Length;
+var map = new int[width, height];
+
+for (int y = 0; y < height; y++)
+{
+    for (int x = 0; x < width; x++)
+    {
+        map[x, y] = input[y][x] - '0';
+    }
+}
+
+var visited = new HashSet<Node>();
+var minDistances = new Dictionary<Node, int>();
+minDistances[new Node((0, 0), (0, 1), 0)] = 0;
+minDistances[new Node((0, 0), (1, 0), 0)] = 0;
+while (true)
+{
+    var minNode = minDistances.OrderBy(x => x.Value).FirstOrDefault();
+    minDistances.Remove(minNode.Key);
+    visited.Add(minNode.Key);
+    var currentNode = minNode.Key;
+    var totalHeat = minNode.Value;
+    var direction = currentNode.Direction;
+    var position = currentNode.Position;
+    var directionSteps = currentNode.DirectionSteps;
+
+    if (currentNode.Position == (width - 1, height - 1) && currentNode.DirectionSteps >= MinDirectionSteps)
+    {
+        Console.WriteLine(totalHeat);
+        break;
+    }
+
+    if (directionSteps < MaxDirectionSteps)
+    {
+        TryNextNode(direction, directionSteps + 1);
+    }
+
+    if (directionSteps >= MinDirectionSteps)
+    {
+        var leftTurn = (direction.Y, -direction.X);
+        TryNextNode(leftTurn, 1);
+        var rightTurn = (-direction.Y, direction.X);
+        TryNextNode(rightTurn, 1);
+    }
+
+    void TryNextNode(Point direction, int steps)
+    {
+        var nextPosition = new Point(position.X + direction.X, position.Y + direction.Y);
+        if (nextPosition.X < 0 || nextPosition.X >= width || nextPosition.Y < 0 || nextPosition.Y >= height)
+        {
+            return;
+        }
+
+        int nextHeat = totalHeat + map[nextPosition.X, nextPosition.Y];
+        var nextNode = new Node(nextPosition, direction, steps);
+
+        if (visited.Contains(nextNode))
+        {
+            return;
+        }
+
+        if (!minDistances.ContainsKey(nextNode) || minDistances[nextNode] > nextHeat)
+        {
+            minDistances[nextNode] = nextHeat;
+        }
+    }
+}
+
+record Node(Point Position, Point Direction, int DirectionSteps);

Day17_2/Properties/launchSettings.json

@@ -0,0 +1,7 @@
+{
+  "profiles": {
+    "Run": {
+      "commandName": "Project"
+    }
+  }
+}