Merge pull request #8 from StevanFreeborn/stevanfreeborn/feat/solve-puzzle-8

feat: solve puzzle 8

01/Trebuchet/Program.cs

@@ -1,4 +1,5 @@
-using System.Text.RegularExpressions;
+using System.Diagnostics;
+using System.Text.RegularExpressions;
 
 namespace Trebuchet;
 
@@ -23,9 +24,15 @@ public class Program
       : new PartOnePuzzleSolver();
 
     var input = await File.ReadAllLinesAsync(args[0]);
+
+    var stopwatch = new Stopwatch();
+    stopwatch.Start();
+
     var result = puzzleSolver.SumCalibrationValues(input);
 
-    Console.WriteLine($"The sum of all calibration values is {result}.");
+    stopwatch.Stop();
+
+    Console.WriteLine($"The sum of all calibration values is {result}. ({stopwatch.ElapsedMilliseconds}ms)");
 
     return result;
   }

08/HauntedWasteland.Tests/GlobalUsings.cs

@@ -0,0 +1,2 @@
+global using Xunit;
+global using FluentAssertions;

08/HauntedWasteland.Tests/HauntedWasteland.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="..\HauntedWasteland\HauntedWasteland.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Content Include="..\INPUT.txt">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
+  </ItemGroup>
+
+</Project>

08/HauntedWasteland.Tests/MapTests.cs

@@ -0,0 +1,118 @@
+namespace HauntedWasteland.Tests;
+
+public class MapTests
+{
+  [Theory]
+  [MemberData(nameof(TestData.ParseMapTestData), MemberType = typeof(TestData))]
+  public void Parse_WhenGivenStringArray_ItShouldReturnMap(string[] input, Map expected)
+  {
+    Map.Parse(input).Should().BeEquivalentTo(expected);
+  }
+
+  [Theory]
+  [MemberData(nameof(TestData.CountStepsTestData), MemberType = typeof(TestData))]
+  public void CountStepsToZ_WhenGivenMap_ItShouldReturnNumberOfSteps(string[] input, int expected)
+  {
+    Map.Parse(input).CountStepsToZ().Should().Be(expected);
+  }
+
+  [Theory]
+  [MemberData(nameof(TestData.CountStepsToAllZNodesData), MemberType = typeof(TestData))]
+  public void CountStepsToAllZNodes_WhenGivenMap_ItShouldReturnNumberOfSteps(string[] input, long expected)
+  {
+    Map.Parse(input).CountStepsToAllZNodes().Should().Be(expected);
+  }
+
+  [Fact]
+  public void FindPrimeFactors_WhenGivenNumber_ItShouldReturnPrimeFactors()
+  {
+    new Map([], []).FindPrimeFactors(11911).Should().BeEquivalentTo([43, 277]);
+  }
+
+  [Fact]
+  public void FindLeastCommonMultiple_WhenGivenNumbers_ItShouldReturnLeastCommonMultiple()
+  {
+    new Map([], []).FindLeastCommonMultiple([16343, 11911, 20221, 21883, 13019, 19667]).Should().Be(13524038372771);
+  }
+
+  public static class TestData
+  {
+    private static readonly string[] MapInput =
+    [
+      "RL",
+      "",
+      "AAA = (BBB, CCC)",
+      "BBB = (DDD, EEE)",
+      "CCC = (ZZZ, GGG)",
+      "DDD = (DDD, DDD)",
+      "EEE = (EEE, EEE)",
+      "GGG = (GGG, GGG)",
+      "ZZZ = (ZZZ, ZZZ)",
+    ];
+
+    private static readonly string[] Input = File.ReadAllLines("INPUT.txt");
+
+    public static IEnumerable<object[]> CountStepsTestData =>
+      new List<object[]>
+      {
+        new object[]
+        {
+          MapInput,
+          2
+        },
+        new object[]
+        {
+          Input,
+          13019
+        }
+      };
+
+    public static IEnumerable<object[]> CountStepsToAllZNodesData =>
+      new List<object[]>
+      {
+        new object[]
+        {
+          new string[]
+          {
+            "LR",
+            "",
+            "11A = (11B, XXX)",
+            "11B = (XXX, 11Z)",
+            "11Z = (11B, XXX)",
+            "22A = (22B, XXX)",
+            "22B = (22C, 22C)",
+            "22C = (22Z, 22Z)",
+            "22Z = (22B, 22B)",
+            "XXX = (XXX, XXX)",
+          },
+          6
+        },
+        new object[]
+        {
+          Input,
+          13524038372771
+        }
+      };
+
+    public static IEnumerable<object[]> ParseMapTestData =>
+      new List<object[]>
+      {
+        new object[]
+        {
+          MapInput,
+          new Map(
+            ['R', 'L'],
+            [
+              new("AAA", "BBB", "CCC"),
+              new("BBB", "DDD", "EEE"),
+              new("CCC", "ZZZ", "GGG"),
+              new("DDD", "DDD", "DDD"),
+              new("EEE", "EEE", "EEE"),
+              new("GGG", "GGG", "GGG"),
+              new("ZZZ", "ZZZ", "ZZZ"),
+            ]
+          )
+        },
+      };
+  }
+}

08/HauntedWasteland.Tests/NodeTests.cs

@@ -0,0 +1,54 @@
+namespace HauntedWasteland.Tests;
+
+public class NodeTests
+{
+  [Theory]
+  [MemberData(nameof(TestData.ParseNodeTestData), MemberType = typeof(TestData))]
+  public void Parse_WhenGivenString_ItShouldReturnNode(string input, Node expected)
+  {
+    Node.Parse(input).Should().BeEquivalentTo(expected);
+  }
+
+  public static class TestData
+  {
+    public static IEnumerable<object[]> ParseNodeTestData =>
+      new List<object[]>
+      {
+        new object[]
+        {
+          "AAA = (BBB, CCC)",
+          new Node("AAA", "BBB", "CCC")
+        },
+        new object[]
+        {
+          "BBB = (DDD, EEE)",
+          new Node("BBB", "DDD", "EEE")
+        },
+        new object[]
+        {
+          "CCC = (ZZZ, GGG)",
+          new Node("CCC", "ZZZ", "GGG")
+        },
+        new object[]
+        {
+          "DDD = (DDD, DDD)",
+          new Node("DDD", "DDD", "DDD")
+        },
+        new object[]
+        {
+          "EEE = (EEE, EEE)",
+          new Node("EEE", "EEE", "EEE")
+        },
+        new object[]
+        {
+          "GGG = (GGG, GGG)",
+          new Node("GGG", "GGG", "GGG")
+        },
+        new object[]
+        {
+          "ZZZ = (ZZZ, ZZZ)",
+          new Node("ZZZ", "ZZZ", "ZZZ")
+        },
+      };
+  }
+}

08/HauntedWasteland/HauntedWasteland.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>

08/HauntedWasteland/Program.cs

@@ -0,0 +1,254 @@
+using System.Diagnostics;
+
+namespace HauntedWasteland;
+
+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 isPart2 = args.Length > 1 && args[1] == "part2";
+    var input = await File.ReadAllLinesAsync(args[0]);
+
+    var stopwatch = new Stopwatch();
+    stopwatch.Start();
+
+    var map = Map.Parse(input);
+    var result = isPart2
+      ? map.CountStepsToAllZNodes()
+      : map.CountStepsToZ();
+
+    stopwatch.Stop();
+
+    Console.WriteLine($"The number of steps is {result}. ({stopwatch.ElapsedMilliseconds}ms)");
+
+    return (int)result;
+  }
+}
+
+/// <summary>
+/// A map of the Haunted Wasteland.
+/// </summary>
+/// <param name="turns">The turns to take at each step.</param>
+/// <param name="nodes">The nodes in the map.</param>
+/// <returns>An instance of <see cref="Map"/>.</returns>
+public class Map(
+  List<char> turns,
+  List<Node> nodes
+)
+{
+  /// <summary>
+  /// Gets the turns to take at each step.
+  /// </summary>
+  public List<char> Turns { get; init; } = turns;
+
+  /// <summary>
+  /// Gets the nodes in the map.
+  /// </summary>
+  public List<Node> Nodes { get; init; } = nodes;
+
+  /// <summary>
+  /// Parses a map from a string array.
+  /// </summary>
+  /// <param name="mapInput">The map input.</param>
+  /// <returns>An instance of <see cref="Map"/>.</returns>
+  public static Map Parse(string[] mapInput)
+  {
+    var turns = mapInput[0].ToList();
+    var nodes = mapInput[2..]
+      .Select(Node.Parse)
+      .ToList();
+
+    return new Map(turns, nodes);
+  }
+
+  /// <summary>
+  /// Counts the number of steps to the Z node.
+  /// </summary>
+  /// <returns>The number of steps to the Z node.</returns>
+  public int CountStepsToZ()
+  {
+    var current = Nodes.First(n => n.Current == "AAA");
+    var steps = 0;
+
+    while (current.Current != "ZZZ")
+    {
+      var next = Turns[steps % Turns.Count] switch
+      {
+        'R' => current.Right,
+        'L' => current.Left,
+        _ => throw new Exception("Invalid turn")
+      };
+      current = Nodes.First(n => n.Current == next);
+      steps++;
+    }
+
+    return steps;
+  }
+
+  /// <summary>
+  /// Finds the prime factors of a number.
+  /// </summary>
+  /// <param name="number">The number to find the prime factors of.</param>
+  /// <returns>The prime factors of the number.</returns>
+  public List<long> FindPrimeFactors(long number)
+  {
+    var factors = new List<long>();
+
+    // Start with the smallest prime number, 2.
+    var divisor = 2;
+
+    // Continue until the number is reduced to 2 or less.
+    while (number >= 2)
+    {
+      // If the number is divisible by the current divisor,
+      if (number % divisor == 0)
+      {
+        // Add the divisor to the list of factors.
+        factors.Add(divisor);
+        // Divide the number by the divisor to reduce it.
+        number /= divisor;
+      }
+      else
+      {
+        // If the number is not divisible by the current divisor, increment the divisor.
+        divisor++;
+      }
+    }
+
+    return factors;
+  }
+
+  /// <summary>
+  /// Finds the least common multiple of a list of numbers.
+  /// </summary>
+  /// <param name="numbers">The numbers to find the least common multiple of.</param>
+  /// <returns>The least common multiple of the numbers.</returns>
+  public long FindLeastCommonMultiple(List<long> numbers)
+  {
+    var primeFactors = numbers.Select(FindPrimeFactors).ToList();
+
+    var uniquePrimeFactors = primeFactors
+      .SelectMany(pf => pf)
+      .Distinct()
+      .ToList();
+
+    var maxPrimeFactors = uniquePrimeFactors
+      .Select(upf => primeFactors.Max(pf => pf.Count(f => f == upf)))
+      .ToList();
+
+    var result = uniquePrimeFactors
+      .Zip(maxPrimeFactors)
+      .Aggregate(
+        (long)1,
+        (acc, b) =>
+          // b.First is the prime factor
+          // b.Second is the number of times it occurs
+          acc * (long)Math.Pow(b.First, b.Second)
+      );
+
+    return result;
+  }
+
+  /// <summary>
+  /// Counts the number of steps to all Z nodes.
+  /// </summary>
+  /// <returns>The number of steps to all Z nodes.</returns>
+  public long CountStepsToAllZNodes()
+  {
+    var startNodes = Nodes.Where(n => n.Current.EndsWith('A')).ToList();
+    var nodeSteps = new List<long>();
+
+    foreach (var startNode in startNodes)
+    {
+      var current = startNode;
+      var steps = 0;
+
+      while (current.Current.EndsWith('Z') is false)
+      {
+        var next = Turns[steps % Turns.Count] switch
+        {
+          'R' => current.Right,
+          'L' => current.Left,
+          _ => throw new Exception("Invalid turn")
+        };
+        current = Nodes.First(n => n.Current == next);
+        steps++;
+      }
+
+      nodeSteps.Add(steps);
+    }
+
+    return FindLeastCommonMultiple(nodeSteps);
+  }
+}
+
+/// <summary>
+/// A node in the map.
+/// </summary>
+/// <param name="current">The current node.</param>
+/// <param name="left">The left node.</param>
+/// <param name="right">The right node.</param>
+/// <returns>An instance of <see cref="Node"/>.</returns>
+public class Node(
+  string current,
+  string left,
+  string right
+)
+{
+  /// <summary>
+  /// Gets the current node.
+  /// </summary>
+  public string Current { get; init; } = current;
+
+  /// <summary>
+  /// Gets the left node.
+  /// </summary>
+  public string Left { get; init; } = left;
+
+  /// <summary>
+  /// Gets the right node.
+  /// </summary>
+  public string Right { get; init; } = right;
+
+  /// <summary>
+  /// Casts the node to a string.
+  /// </summary>
+  public override string ToString()
+  {
+    return $"{Current} = ({Left},{Right})";
+  }
+
+  /// <summary>
+  /// Parses a node from a string.
+  /// </summary>
+  /// <param name="nodeString">The node string.</param>
+  /// <returns>An instance of <see cref="Node"/>.</returns>
+  public static Node Parse(string nodeString)
+  {
+    var parts = nodeString.Split(
+      '=',
+      StringSplitOptions.TrimEntries | StringSplitOptions.RemoveEmptyEntries
+    );
+    var current = parts[0];
+    var nextNodes = parts[1].Split(
+      ',',
+      StringSplitOptions.TrimEntries | StringSplitOptions.RemoveEmptyEntries
+    );
+    var left = nextNodes[0].Trim('(');
+    var right = nextNodes[1].Trim(')');
+
+    return new Node(current, left, right);
+  }
+}

AdventOfCode2023.sln

@@ -45,6 +45,12 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CamelCards", "07\CamelCards
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CamelCards.Tests", "07\CamelCards.Tests\CamelCards.Tests.csproj", "{8F04A78E-D2E1-41AC-B43C-74608B7B4FCB}"
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "08", "08", "{F21CCF39-1F8A-40DA-A0E5-F1426B09BAA2}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "HauntedWasteland", "08\HauntedWasteland\HauntedWasteland.csproj", "{332B56C1-8ECB-4E34-9E69-54BF6A192CFB}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "HauntedWasteland.Tests", "08\HauntedWasteland.Tests\HauntedWasteland.Tests.csproj", "{FA8DDDD1-4DD9-4927-A9FB-C4FACDEAF901}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -110,6 +116,14 @@ Global
 		{8F04A78E-D2E1-41AC-B43C-74608B7B4FCB}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{8F04A78E-D2E1-41AC-B43C-74608B7B4FCB}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{8F04A78E-D2E1-41AC-B43C-74608B7B4FCB}.Release|Any CPU.Build.0 = Release|Any CPU
+		{332B56C1-8ECB-4E34-9E69-54BF6A192CFB}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{332B56C1-8ECB-4E34-9E69-54BF6A192CFB}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{332B56C1-8ECB-4E34-9E69-54BF6A192CFB}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{332B56C1-8ECB-4E34-9E69-54BF6A192CFB}.Release|Any CPU.Build.0 = Release|Any CPU
+		{FA8DDDD1-4DD9-4927-A9FB-C4FACDEAF901}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{FA8DDDD1-4DD9-4927-A9FB-C4FACDEAF901}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{FA8DDDD1-4DD9-4927-A9FB-C4FACDEAF901}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{FA8DDDD1-4DD9-4927-A9FB-C4FACDEAF901}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(NestedProjects) = preSolution
 		{3F8EAC09-4BC7-43AA-B72B-48DDD2710F6D} = {8C29858C-623A-461A-BF0B-254E151CD9C2}
@@ -126,5 +140,7 @@ Global
 		{8C89E1D0-2617-4B89-BA9C-9189FC69BC43} = {86704890-D6B8-4166-853B-F1424B8396C7}
 		{DC16CBE1-B1FA-4E6B-AAD8-43CDECA46659} = {7F8AD027-D8D7-407B-9E08-B363B7B34621}
 		{8F04A78E-D2E1-41AC-B43C-74608B7B4FCB} = {7F8AD027-D8D7-407B-9E08-B363B7B34621}
+		{332B56C1-8ECB-4E34-9E69-54BF6A192CFB} = {F21CCF39-1F8A-40DA-A0E5-F1426B09BAA2}
+		{FA8DDDD1-4DD9-4927-A9FB-C4FACDEAF901} = {F21CCF39-1F8A-40DA-A0E5-F1426B09BAA2}
 	EndGlobalSection
 EndGlobal

README.md

@@ -42,30 +42,30 @@ dotnet build
 
 ## Challenges
 
-| Day | Problem                    |            Solution             | Status | Notes                                                                                                   |
+| Day | Problem                    |              Solution              | Status | Notes                                                                                                   |
-| --- | -------------------------- | :-----------------------------: | :----: | ------------------------------------------------------------------------------------------------------- |
+| --- | -------------------------- | :--------------------------------: | :----: | ------------------------------------------------------------------------------------------------------- |
-| 01  | [Problem](./01/PROBLEM.md) |   [Solution](./01/Trebuchet/)   |   ✅   | The trickiest part here was accounting for overlapping digit words.                                     |
+| 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.                                          |
+| 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.                                     |
+| 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/Scratchcards/)  |   ✅   | Part 2 gets out of hand quickly with just 200 cards.                                                    |
+| 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/IYGASAF/)    |   ✅   | I brute forced part 2 using parallelism. I know shame.                                                  |
+| 05  | [Problem](./05/PROBLEM.md) |     [Solution](./05/IYGASAF/)      |   ✅   | I brute forced part 2 using parallelism. I know shame.                                                  |
-| 06  | [Problem](./06/PROBLEM.md) |   [Solution](./06/WaitForIt/)   |   ✅   | Thank goodness part 2 was not like 5's part 2. 😅                                                       |
+| 06  | [Problem](./06/PROBLEM.md) |    [Solution](./06/WaitForIt/)     |   ✅   | Thank goodness part 2 was not like 5's part 2. 😅                                                       |
-| 07  | [Problem](./07/PROBLEM.md) |  [Solution](./07/CamelCards/)   |   ✅   | What took me longest here was I missed a case when jokers are wild and there are three groups of cards. |
+| 07  | [Problem](./07/PROBLEM.md) |    [Solution](./07/CamelCards/)    |   ✅   | What took me longest here was I missed a case when jokers are wild and there are three groups of cards. |
-| 08  | [Problem](./08/PROBLEM.md) |        [Solution](./08/)        |   ⌛   |
+| 08  | [Problem](./08/PROBLEM.md) | [Solution](./08/HauntedWasteland/) |   ✅   | Got to implement a least common multiple algorithm for part 2.                                          |
-| 09  | [Problem](./09/PROBLEM.md) |        [Solution](./09/)        |   ⌛   |
+| 09  | [Problem](./09/PROBLEM.md) |         [Solution](./09/)          |   ⌛   |
-| 10  | [Problem](./10/PROBLEM.md) |        [Solution](./10/)        |   ⌛   |
+| 10  | [Problem](./10/PROBLEM.md) |         [Solution](./10/)          |   ⌛   |
-| 11  | [Problem](./11/PROBLEM.md) |        [Solution](./11/)        |   ⌛   |
+| 11  | [Problem](./11/PROBLEM.md) |         [Solution](./11/)          |   ⌛   |
-| 12  | [Problem](./12/PROBLEM.md) |        [Solution](./12/)        |   ⌛   |
+| 12  | [Problem](./12/PROBLEM.md) |         [Solution](./12/)          |   ⌛   |
-| 13  | [Problem](./13/PROBLEM.md) |        [Solution](./13/)        |   ⌛   |
+| 13  | [Problem](./13/PROBLEM.md) |         [Solution](./13/)          |   ⌛   |
-| 14  | [Problem](./14/PROBLEM.md) |        [Solution](./14/)        |   ⌛   |
+| 14  | [Problem](./14/PROBLEM.md) |         [Solution](./14/)          |   ⌛   |
-| 15  | [Problem](./15/PROBLEM.md) |        [Solution](./15/)        |   ⌛   |
+| 15  | [Problem](./15/PROBLEM.md) |         [Solution](./15/)          |   ⌛   |
-| 16  | [Problem](./16/PROBLEM.md) |        [Solution](./16/)        |   ⌛   |
+| 16  | [Problem](./16/PROBLEM.md) |         [Solution](./16/)          |   ⌛   |
-| 17  | [Problem](./17/PROBLEM.md) |        [Solution](./17/)        |   ⌛   |
+| 17  | [Problem](./17/PROBLEM.md) |         [Solution](./17/)          |   ⌛   |
-| 18  | [Problem](./18/PROBLEM.md) |        [Solution](./18/)        |   ⌛   |
+| 18  | [Problem](./18/PROBLEM.md) |         [Solution](./18/)          |   ⌛   |
-| 19  | [Problem](./19/PROBLEM.md) |        [Solution](./19/)        |   ⌛   |
+| 19  | [Problem](./19/PROBLEM.md) |         [Solution](./19/)          |   ⌛   |
-| 20  | [Problem](./20/PROBLEM.md) |        [Solution](./20/)        |   ⌛   |
+| 20  | [Problem](./20/PROBLEM.md) |         [Solution](./20/)          |   ⌛   |
-| 21  | [Problem](./21/PROBLEM.md) |        [Solution](./21/)        |   ⌛   |
+| 21  | [Problem](./21/PROBLEM.md) |         [Solution](./21/)          |   ⌛   |
-| 22  | [Problem](./22/PROBLEM.md) |        [Solution](./22/)        |   ⌛   |
+| 22  | [Problem](./22/PROBLEM.md) |         [Solution](./22/)          |   ⌛   |
-| 23  | [Problem](./23/PROBLEM.md) |        [Solution](./23/)        |   ⌛   |
+| 23  | [Problem](./23/PROBLEM.md) |         [Solution](./23/)          |   ⌛   |
-| 24  | [Problem](./24/PROBLEM.md) |        [Solution](./24/)        |   ⌛   |
+| 24  | [Problem](./24/PROBLEM.md) |         [Solution](./24/)          |   ⌛   |
-| 25  | [Problem](./25/PROBLEM.md) |        [Solution](./25/)        |   ⌛   |
+| 25  | [Problem](./25/PROBLEM.md) |         [Solution](./25/)          |   ⌛   |