Merge pull request #4 from StevanFreeborn/stevanfreeborn/feat/solve-puzzle-4

feat: solve puzzle 4

03/GearRatios.Tests/GearRatios.Tests.csproj

@@ -27,4 +27,10 @@
     <ProjectReference Include="..\GearRatios\GearRatios.csproj" />
   </ItemGroup>
 
+  <ItemGroup>
+    <Content Include="..\INPUT.txt">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
+  </ItemGroup>
+
 </Project>

03/GearRatios.Tests/PuzzleSolverTests.cs

@@ -36,6 +36,8 @@ public class PuzzleSolverTests
       ".664.598..",
     ];
 
+    private static readonly string[] Input = File.ReadAllLines("INPUT.txt");
+
     public static IEnumerable<object[]> SumGearRatios =>
       new List<object[]>
       {
@@ -44,6 +46,11 @@ public class PuzzleSolverTests
           TestSchematic,
           467835,
         },
+        new object[]
+        {
+          Input,
+          81997870,
+        }
       };
 
     public static IEnumerable<object?[]> SumPartNumbersData =>
@@ -84,6 +91,11 @@ public class PuzzleSolverTests
             "........375...%.........*......450.456.$.........714........851.327..#...+......*...+.......179.630....854.................................*",
           },
           11612
+        },
+        new object[]
+        {
+          Input,
+          550934,
         }
       };
   }

04/Scratchcards.Tests/CardTests.cs

@@ -0,0 +1,105 @@
+namespace Scratchcards.Tests;
+
+public class CardTests
+{
+  [Theory]
+  [MemberData(nameof(TestData.ParseCardData), MemberType = typeof(TestData))]
+  public void Parse_GivenInput_ItShouldReturnExpectedCard(string input, Card expected)
+  {
+    var result = Card.Parse(input);
+    result.Should().BeEquivalentTo(expected);
+  }
+
+  [Theory]
+  [MemberData(nameof(TestData.GetCardValueData), MemberType = typeof(TestData))]
+  public void GetCardValue_GivenCard_ItShouldReturnExpectedValue(Card card, int expected)
+  {
+    var result = card.GetCardValue();
+    result.Should().Be(expected);
+  }
+
+  public static class TestData
+  {
+    private static readonly Dictionary<string, Card> TestCards =
+      new()
+      {
+        {
+          "Card 1: 41 48 83 86 17 | 83 86  6 31 17  9 48 53",
+          new Card(
+            1,
+            [41, 48, 83, 86, 17],
+            [83, 86, 6, 31, 17, 9, 48, 53]
+          )
+        },
+        {
+          "Card 2: 13 32 20 16 61 | 61 30 68 82 17 32 24 19",
+          new Card(
+            2,
+            [13, 32, 20, 16, 61],
+            [61, 30, 68, 82, 17, 32, 24, 19]
+          )
+        },
+        {
+          "Card 3:  1 21 53 59 44 | 69 82 63 72 16 21 14  1",
+          new Card(
+            3,
+            [1, 21, 53, 59, 44],
+            [69, 82, 63, 72, 16, 21, 14, 1]
+          )
+        },
+        {
+          "Card 4: 41 92 73 84 69 | 59 84 76 51 58  5 54 83",
+          new Card(
+            4,
+            [41, 92, 73, 84, 69],
+            [59, 84, 76, 51, 58, 5, 54, 83]
+          )
+        },
+        {
+          "Card 5: 87 83 26 28 32 | 88 30 70 12 93 22 82 36",
+          new Card(
+            5,
+            [87, 83, 26, 28, 32],
+            [88, 30, 70, 12, 93, 22, 82, 36]
+          )
+        },
+        {
+          "Card 6: 31 18 13 56 72 | 74 77 10 23 35 67 36 11",
+          new Card(
+            6,
+            [31, 18, 13, 56, 72],
+            [74, 77, 10, 23, 35, 67, 36, 11]
+          )
+        },
+      };
+
+    public static IEnumerable<object[]> ParseCardData =>
+      TestCards
+        .Select(kvp => new object[] { kvp.Key, kvp.Value })
+        .ToList();
+
+    public static IEnumerable<object[]> GetCardValueData()
+    {
+      for (var i = 0; i < TestCards.Count; i++)
+      {
+        var currentCard = TestCards.ElementAt(i);
+        var expectedValue = i switch
+        {
+          0 => 8,
+          1 => 2,
+          2 => 2,
+          3 => 1,
+          4 => 0,
+          5 => 0,
+          _ => throw new Exception("Unexpected card index"),
+        };
+
+        yield return new object[]
+        {
+          currentCard.Value,
+          expectedValue
+        };
+      }
+    }
+  }
+}

04/Scratchcards.Tests/GlobalUsings.cs

@@ -0,0 +1,3 @@
+global using FluentAssertions;
+
+global using Xunit;

04/Scratchcards.Tests/PuzzleSolverTests.cs

@@ -0,0 +1,67 @@
+namespace Scratchcards.Tests;
+
+public class PuzzleSolverTests
+{
+  private readonly PuzzleSolver _sut = new();
+
+  [Theory]
+  [MemberData(nameof(TestData.SumCardValuesData), MemberType = typeof(TestData))]
+  public void SumCardValues_GivenCards_ItShouldReturnExpectedValue(string[] cards, int expected)
+  {
+    var result = _sut.SumCardValues(cards);
+    result.Should().Be(expected);
+  }
+
+  [Theory]
+  [MemberData(nameof(TestData.GetTotalCardCountData), MemberType = typeof(TestData))]
+  public void GetTotalCardCount_GivenCards_ItShouldReturnExpectedValue(string[] cards, int expected)
+  {
+    var result = _sut.GetTotalCardCount(cards);
+    result.Should().Be(expected);
+  }
+
+  public static class TestData
+  {
+    private static readonly string[] ExampleInput =
+    [
+      "Card 1: 41 48 83 86 17 | 83 86  6 31 17  9 48 53",
+      "Card 2: 13 32 20 16 61 | 61 30 68 82 17 32 24 19",
+      "Card 3:  1 21 53 59 44 | 69 82 63 72 16 21 14  1",
+      "Card 4: 41 92 73 84 69 | 59 84 76 51 58  5 54 83",
+      "Card 5: 87 83 26 28 32 | 88 30 70 12 93 22 82 36",
+      "Card 6: 31 18 13 56 72 | 74 77 10 23 35 67 36 11",
+    ];
+
+    private static string[] Input => File.ReadAllLines("INPUT.txt");
+
+    public static IEnumerable<object[]> GetTotalCardCountData =>
+      new List<object[]>
+      {
+        new object[]
+        {
+          ExampleInput,
+          30,
+        },
+        new object[]
+        {
+          Input,
+          5920640,
+        },
+      };
+
+    public static IEnumerable<object[]> SumCardValuesData =>
+      new List<object[]>
+      {
+        new object[]
+        {
+          ExampleInput,
+          13,
+        },
+        new object[]
+        {
+          Input,
+          23235,
+        },
+      };
+  }
+}

04/Scratchcards.Tests/Scratchcards.Tests.csproj

@@ -0,0 +1,36 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+
+    <IsPackable>false</IsPackable>
+    <IsTestProject>true</IsTestProject>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="FluentAssertions" Version="6.12.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.6.0" />
+    <PackageReference Include="xunit" Version="2.4.2" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5">
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      <PrivateAssets>all</PrivateAssets>
+    </PackageReference>
+    <PackageReference Include="coverlet.collector" Version="6.0.0">
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      <PrivateAssets>all</PrivateAssets>
+    </PackageReference>
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Scratchcards\Scratchcards.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Content Include="..\INPUT.txt">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
+  </ItemGroup>
+
+</Project>

04/Scratchcards/Program.cs

@@ -0,0 +1,171 @@
+namespace Scratchcards;
+
+public class Program
+{
+  public static async Task<int> Main(string[] args)
+  {
+    if (args.Length is 0)
+    {
+      Console.WriteLine("Please provide a path to the input file.");
+      return -1;
+    }
+
+    if (File.Exists(args[0]) is false)
+    {
+      Console.WriteLine("The provided file does not exist.");
+      return -2;
+    }
+
+    var puzzleSolver = new PuzzleSolver();
+
+    var input = await File.ReadAllLinesAsync(args[0]);
+    var result = args.Length is 2 && args[1] == "part2"
+      ? puzzleSolver.GetTotalCardCount(input)
+      : puzzleSolver.SumCardValues(input);
+
+    if (args.Length is 2 && args[1] == "part2")
+    {
+      Console.WriteLine($"The total number of cards is {result}.");
+    }
+    else
+    {
+      Console.WriteLine($"The total value of the cards is {result}.");
+    }
+
+    return result;
+  }
+}
+
+/// <summary>
+/// Solves the puzzle.
+/// </summary>
+public class PuzzleSolver
+{
+  /// <summary>
+  /// Sums the value of the cards.
+  /// </summary>
+  /// <param name="cards">The cards.</param>
+  /// <returns>The sum of the cards.</returns>
+  public int SumCardValues(string[] cards) => cards
+    .Select(Card.Parse)
+    .Sum(c => c.GetCardValue());
+
+  /// <summary>
+  /// Gets the total number of cards.
+  /// </summary>
+  /// <param name="cards">The cards.</param>
+  /// <returns>The total number of cards.</returns>
+  public int GetTotalCardCount(string[] cards)
+  {
+    var cardStringsToProcess = new List<string>(cards);
+
+    for (var i = 0; i < cardStringsToProcess.Count; i++)
+    {
+      var currentCardString = cardStringsToProcess[i];
+      var currentCardStringIndex = Array.IndexOf(cards, currentCardString);
+      var currentCard = Card.Parse(currentCardString);
+      var numOfMatchingNumbersForCurrentCard = currentCard.MatchingNumbers.Count;
+      var cardIndexesToCopy = Enumerable.Range(
+        currentCardStringIndex + 1,
+        Math.Min(
+          numOfMatchingNumbersForCurrentCard,
+          cards.Length - currentCardStringIndex - 1
+        )
+      );
+
+      foreach (var index in cardIndexesToCopy)
+      {
+        cardStringsToProcess.Add(cards[index]);
+      }
+    }
+
+    return cardStringsToProcess.Count;
+  }
+}
+
+/// <summary>
+/// Represents a card.
+/// </summary>
+/// <param name="id">The identifier.</param>
+/// <param name="winningNumbers">The winning numbers.</param>
+/// <param name="numbers">The numbers.</param>
+/// <returns>An instance of <see cref="Card"/>.</returns>
+public class Card(
+  int id,
+  List<int> winningNumbers,
+  List<int> numbers
+)
+{
+  /// <summary>
+  /// Gets the identifier.
+  /// </summary>
+  public int Id { get; init; } = id;
+
+  /// <summary>
+  /// Gets the winning numbers.
+  /// </summary>
+  public List<int> WinningNumbers { get; init; } = winningNumbers;
+
+  /// <summary>
+  /// Gets the numbers.
+  /// </summary>
+  public List<int> Numbers { get; init; } = numbers;
+
+  /// <summary>
+  /// Gets the matching numbers.
+  /// </summary>
+  public List<int> MatchingNumbers => Numbers.Intersect(WinningNumbers).ToList();
+
+  /// <summary>
+  /// Gets the value of the card.
+  /// </summary>
+  /// <returns>The value of the card.</returns>
+  public int GetCardValue() => MatchingNumbers.Count is 1
+    ? 1
+    : (int)Math.Pow(2, MatchingNumbers.Count - 1);
+
+  /// <summary>
+  /// Parses the specified input.
+  /// </summary>
+  /// <param name="input">The input.</param>
+  /// <returns>An instance of <see cref="Card"/>.</returns>
+  public static Card Parse(string input)
+  {
+    var parts = input.Split(':');
+    var cardId = int.Parse(
+      parts[0].Split(
+        ' ',
+        StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries
+      )[1]
+    );
+
+    var numberStrings = parts[1].Trim();
+    var numberParts = numberStrings
+      .Split('|')
+      .Select(s => s.Trim())
+      .ToArray();
+
+    var winningNumbersString = numberParts[0];
+    var numbersString = numberParts[1];
+
+    var winningNumbers = winningNumbersString
+      .Split(
+        ' ',
+        StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries
+      )
+      .Select(s => s.Trim())
+      .Select(int.Parse)
+      .ToList();
+
+    var numbers = numbersString
+      .Split(
+        ' ',
+        StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries
+      )
+      .Select(s => s.Trim())
+      .Select(int.Parse)
+      .ToList();
+
+    return new Card(cardId, winningNumbers, numbers);
+  }
+}

04/Scratchcards/Scratchcards.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

AdventOfCode2023.sln

@@ -21,6 +21,12 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "GearRatios", "03\GearRatios
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "GearRatios.Tests", "03\GearRatios.Tests\GearRatios.Tests.csproj", "{FEE9253C-A56B-4735-BDB3-C62220C5B1B1}"
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "04", "04", "{522D6D1E-54AD-4479-BB78-0AB5D7493EFC}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Scratchcards", "04\Scratchcards\Scratchcards.csproj", "{B58CF14B-97A1-45F6-967F-29FA82DAFD0F}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Scratchcards.Tests", "04\Scratchcards.Tests\Scratchcards.Tests.csproj", "{FF8A5512-85FD-45E7-9F97-EC528465949C}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -54,6 +60,14 @@ Global
 		{FEE9253C-A56B-4735-BDB3-C62220C5B1B1}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{FEE9253C-A56B-4735-BDB3-C62220C5B1B1}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{FEE9253C-A56B-4735-BDB3-C62220C5B1B1}.Release|Any CPU.Build.0 = Release|Any CPU
+		{B58CF14B-97A1-45F6-967F-29FA82DAFD0F}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{B58CF14B-97A1-45F6-967F-29FA82DAFD0F}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{B58CF14B-97A1-45F6-967F-29FA82DAFD0F}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{B58CF14B-97A1-45F6-967F-29FA82DAFD0F}.Release|Any CPU.Build.0 = Release|Any CPU
+		{FF8A5512-85FD-45E7-9F97-EC528465949C}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{FF8A5512-85FD-45E7-9F97-EC528465949C}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{FF8A5512-85FD-45E7-9F97-EC528465949C}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{FF8A5512-85FD-45E7-9F97-EC528465949C}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(NestedProjects) = preSolution
 		{3F8EAC09-4BC7-43AA-B72B-48DDD2710F6D} = {8C29858C-623A-461A-BF0B-254E151CD9C2}
@@ -62,5 +76,7 @@ Global
 		{4825CE42-4717-4DA6-944F-9BD9A825932B} = {4FD81B09-302F-4C76-BECB-B4559DF3984F}
 		{F697AC19-C92D-4E2A-975A-1A16A1961133} = {EA04152D-316A-4AA4-9BC1-57F6A9F3CD4E}
 		{FEE9253C-A56B-4735-BDB3-C62220C5B1B1} = {EA04152D-316A-4AA4-9BC1-57F6A9F3CD4E}
+		{B58CF14B-97A1-45F6-967F-29FA82DAFD0F} = {522D6D1E-54AD-4479-BB78-0AB5D7493EFC}
+		{FF8A5512-85FD-45E7-9F97-EC528465949C} = {522D6D1E-54AD-4479-BB78-0AB5D7493EFC}
 	EndGlobalSection
 EndGlobal

README.md

@@ -40,7 +40,7 @@ dotnet run -- <path-to-input-file> part2
 | 01  | [Problem](./01/PROBLEM.md) |   [Solution](./01/Trebuchet/)   |   ✅   | The trickiest part here was accounting for overlapping digit words. |
 | 02  | [Problem](./02/PROBLEM.md) | [Solution](./02/CubeConundrum/) |   ✅   | The key to me here was to parse the input into a useful model.      |
 | 03  | [Problem](./03/PROBLEM.md) |  [Solution](./03/GearRatios/)   |   ✅   | The edge case that got me here was lines ending with a part number. |
-| 04  | [Problem](./04/PROBLEM.md) |        [Solution](./04/)        |   ⌛   |
+| 04  | [Problem](./04/PROBLEM.md) | [Solution](./04/Scratchcards/)  |   ✅   | Part 2 gets out of hand quickly with just 200 cards.                |
 | 05  | [Problem](./05/PROBLEM.md) |        [Solution](./05/)        |   ⌛   |
 | 06  | [Problem](./06/PROBLEM.md) |        [Solution](./06/)        |   ⌛   |
 | 07  | [Problem](./07/PROBLEM.md) |        [Solution](./07/)        |   ⌛   |