feat: solve puzzle 3

01/Trebuchet/Program.cs

@@ -9,16 +9,16 @@ public class Program
     if (args.Length is 0)
     {
       Console.WriteLine("Please provide a path to the input file.");
-      return 1;
+      return -1;
     }
 
     if (File.Exists(args[0]) is false)
     {
       Console.WriteLine("The provided file does not exist.");
-      return 2;
+      return -2;
     }
 
-    IPuzzleSolver puzzleSolver = args.Length > 1 && args[1] == "2"
+    IPuzzleSolver puzzleSolver = args.Length > 1 && args[1] == "part2"
       ? new PartTwoPuzzleSolver()
       : new PartOnePuzzleSolver();
 
@@ -27,7 +27,7 @@ public class Program
 
     Console.WriteLine($"The sum of all calibration values is {result}.");
 
-    return 0;
+    return result;
   }
 }
 

02/CubeConundrum/Program.cs

@@ -26,7 +26,14 @@ public class Program
       ? puzzleSolver.SumGameMinimumPowers(games)
       : puzzleSolver.SumPossibleGameIds(games);
 
+    if (args.Length > 1 && args[1] == "part2")
+    {
+      Console.WriteLine($"The sum of the minimum powers of all games is {result}.");
+    }
+    else
+    {
       Console.WriteLine($"The sum of all possible game ids is {result}.");
+    }
 
     return result;
   }

03/GearRatios.Test/GlobalUsings.cs

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

03/GearRatios.Test/UnitTest1.cs

@@ -1,10 +0,0 @@
-namespace GearRatios.Test;
-
-public class UnitTest1
-{
-    [Fact]
-    public void Test1()
-    {
-
-    }
-}

03/GearRatios.Tests/GearRatios.Tests.csproj

@@ -10,6 +10,7 @@
   </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">

03/GearRatios.Tests/GlobalUsings.cs

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

03/GearRatios.Tests/LineTests.cs

@@ -0,0 +1,353 @@
+namespace GearRatios.Test;
+
+public class LineTests
+{
+  [Theory, MemberData(nameof(TestData.LineData), MemberType = typeof(TestData))]
+  public void Parse_GivenLine_ItShouldParseExpectedValues(string line, Line expected)
+  {
+    var actual = Line.Parse(line);
+    actual.Should().BeEquivalentTo(expected);
+  }
+
+  [Theory, MemberData(nameof(TestData.PartNumberData), MemberType = typeof(TestData))]
+  public void GetPartNumbers_GivenLine_ItShouldReturnExpectedValues(Line currentLine, Line? prevLine, Line? nextLine, List<int> expected)
+  {
+    var actual = currentLine.GetPartNumbers(prevLine, nextLine);
+    actual.Should().BeEquivalentTo(expected);
+  }
+
+  [Theory, MemberData(nameof(TestData.GearData), MemberType = typeof(TestData))]
+  public void GetGearRatios_GivenLine_ItShouldReturnExpectedValues(Line currentLine, Line? prevLine, Line? nextLine, List<int> expected)
+  {
+    var actual = currentLine.GetGearRatios(prevLine, nextLine);
+    actual.Should().BeEquivalentTo(expected);
+  }
+
+
+  public static class TestData
+  {
+    public static IEnumerable<object?[]> GearData =>
+      new List<object?[]>
+      {
+        new object?[]
+        {
+          new Line(
+            [],
+            []
+          ),
+          null,
+          null,
+          new List<int>(),
+        },
+        new object?[]
+        {
+          new Line(
+            [
+              new()
+              {
+                { 467, new Indexes(0, 2) },
+              },
+              new()
+              {
+                { 114, new Indexes(5, 7) },
+              },
+            ],
+            [
+            ]
+          ),
+          null,
+          null,
+          new List<int>(),
+        },
+        new object?[]
+        {
+          new Line(
+            [],
+            [
+              new()
+              {
+                { "*", new Indexes(3, 3) },
+              },
+            ]
+          ),
+          null,
+          null,
+          new List<int>(),
+        },
+        new object?[]
+        {
+          new Line(
+            [
+              new()
+              {
+                { 617, new Indexes(0, 2) },
+                { 114, new Indexes(4, 6) },
+              },
+            ],
+            [
+              new()
+              {
+                { "*", new Indexes(3, 3) },
+              },
+            ]
+          ),
+          null,
+          null,
+          new List<int> { 617 * 114 },
+        },
+        new object?[]
+        {
+          new Line(
+            [],
+            [
+              new()
+              {
+                { "*", new Indexes(3, 3) },
+              },
+            ]
+          ),
+          new Line(
+            [
+              new()
+              {
+                { 467, new Indexes(0, 2) },
+              },
+              new()
+              {
+                { 114, new Indexes(5, 7) },
+              },
+            ],
+            []
+          ),
+          new Line(
+            [
+              new()
+              {
+                { 35, new Indexes(2, 3) },
+              },
+              new()
+              {
+                { 633, new Indexes(6, 8) },
+              },
+            ],
+            []
+          ),
+          new List<int> { 467 * 35 },
+        }
+      };
+
+    public static IEnumerable<object?[]> PartNumberData =>
+      new List<object?[]>
+      {
+        new object?[]
+        {
+          new Line(
+            [
+              new()
+              {
+                { 467, new Indexes(0, 2) },
+              },
+              new()
+              {
+                { 114, new Indexes(5, 7) },
+              },
+            ],
+            [
+            ]
+          ),
+          null,
+          null,
+          new List<int>(),
+        },
+        new object?[]
+        {
+          new Line(
+            [],
+            [
+              new()
+              {
+                { "*", new Indexes(3, 3) },
+              },
+            ]
+          ),
+          null,
+          null,
+          new List<int>(),
+        },
+        new object?[]
+        {
+          new Line(
+            [
+              new()
+              {
+                { 617, new Indexes(0, 2) },
+              },
+            ],
+            [
+              new()
+              {
+                { "*", new Indexes(3, 3) },
+              },
+            ]
+          ),
+          null,
+          null,
+          new List<int> { 617 },
+        },
+        new object?[]
+        {
+          new Line(
+            [
+              new()
+              {
+                { 617, new Indexes(0, 2) },
+              },
+              new()
+              {
+                { 114, new Indexes(6, 8) },
+              },
+            ],
+            [
+              new()
+              {
+                { "*", new Indexes(3, 3) },
+              },
+              new()
+              {
+                { "*", new Indexes(9, 9) },
+              },
+            ]
+          ),
+          null,
+          null,
+          new List<int> { 617, 114 },
+        },
+        new object?[]
+        {
+          new Line(
+            [
+              new()
+              {
+                { 467, new Indexes(0, 2) },
+              },
+              new()
+              {
+                { 114, new Indexes(5, 7) },
+              },
+            ],
+            [
+            ]
+          ),
+          null,
+          new Line(
+            [],
+            [
+              new()
+              {
+                { "*", new Indexes(3, 3) },
+              },
+            ]
+          ),
+          new List<int>() { 467 },
+        },
+        new object?[]
+        {
+          new Line(
+            [
+              new()
+              {
+                { 58, new Indexes(7, 8) },
+              },
+            ],
+            [
+              new()
+              {
+                { "+", new Indexes(5, 5) },
+              },
+            ]
+          ),
+          new Line(
+            [
+              new()
+              {
+                { 617, new Indexes(0, 2) },
+              },
+            ],
+            [
+              new()
+              {
+                { "*", new Indexes(3, 3) },
+              },
+            ]
+          ),
+          new Line(
+            [
+              new()
+              {
+                { 592, new Indexes(2, 4) },
+              },
+            ],
+            []
+          ),
+          new List<int>(),
+        },
+      };
+
+    public static IEnumerable<object[]> LineData =>
+      new List<object[]>
+      {
+        new object[]
+        {
+          "467..114..",
+          new Line(
+            [
+              new()
+              {
+                { 467, new Indexes(0, 2) },
+              },
+              new()
+              {
+                { 114, new Indexes(5, 7) },
+              },
+            ],
+            []
+        ),
+        },
+        new object[]
+        {
+          "...*......",
+          new Line(
+            [],
+            [
+              new()
+              {
+                { "*", new Indexes(3, 3) },
+              },
+            ]
+          ),
+        },
+        new object[]
+        {
+          "...41+...564",
+          new Line(
+            [
+              new()
+              {
+                { 41, new Indexes(3, 4) },
+              },
+              new()
+              {
+                { 564, new Indexes(9, 11) },
+              },
+            ],
+            [
+              new()
+              {
+                { "+", new Indexes(5, 5) },
+              },
+            ]
+          ),
+        }
+      };
+  };
+}

03/GearRatios.Tests/PuzzleSolverTests.cs

@@ -0,0 +1,90 @@
+namespace GearRatios.Test;
+
+public class PuzzleSolverTests
+{
+  private readonly PuzzleSolver _sut = new();
+
+  [Theory]
+  [MemberData(nameof(TestData.SumPartNumbersData), MemberType = typeof(TestData))]
+  public void SumPartNumbers_GivenSchematic_ItShouldReturnExpectedValue(string[] schematic, int expected)
+  {
+    var actual = _sut.SumPartNumbers(schematic);
+    actual.Should().Be(expected);
+  }
+
+  [Theory]
+  [MemberData(nameof(TestData.SumGearRatios), MemberType = typeof(TestData))]
+  public void SumGearRatios_GivenSchematic_ItShouldReturnExpectedValue(string[] schematic, int expected)
+  {
+    var actual = _sut.SumGearRatios(schematic);
+    actual.Should().Be(expected);
+  }
+
+  public static class TestData
+  {
+    private static readonly string[] TestSchematic =
+    [
+      "467..114..",
+      "...*......",
+      "..35..633.",
+      "......#...",
+      "617*......",
+      ".....+.58.",
+      "..592.....",
+      "......755.",
+      "...$.*....",
+      ".664.598..",
+    ];
+
+    public static IEnumerable<object[]> SumGearRatios =>
+      new List<object[]>
+      {
+        new object[]
+        {
+          TestSchematic,
+          467835,
+        },
+      };
+
+    public static IEnumerable<object?[]> SumPartNumbersData =>
+      new List<object?[]>
+      {
+        new object?[]
+        {
+          TestSchematic,
+          4361,
+        },
+        new object[]
+        {
+          new[]
+          {
+            "...................305.124................................432..............................................576..313.....514.................",
+            ".............113...-......&....................&...819...........654..../..........................&901................*....869.257.........",
+            "...377..&783../.................................9...........855*......940..463................-.........................844.*....@......679.",
+            "......*...........197.261.....817..336.759............&742......548.......&........748......844.............#.......&........254...169..*...",
+          },
+          10421,
+        },
+        new object[]
+        {
+          new[]
+          {
+            ".............................457....834.....................94..564..........&.........498....*...304....../...*.....*..........845.....&...",
+            ".......12*48.753...244..196....=......$..721....90*29.........*.................+.522.......487...............317.....531..311........20....",
+            ".177...............*.....*.................*.............*969.611.......*565..338...*.............712..922$.......770......*....522.........",
+          },
+          8318
+        },
+        new object[]
+        {
+          new[]
+          {
+            "663..462...........*..........109..706*.................=.............553........712......*971......674.396...635*..........................",
+            "........../...728.952...413......*......744.......%..........................300..*....782................*.......742..&424........41+...564",
+            "........375...%.........*......450.456.$.........714........851.327..#...+......*...+.......179.630....854.................................*",
+          },
+          11612
+        }
+      };
+  }
+}

03/GearRatios/Program.cs

@@ -1,2 +1,228 @@
-// See https://aka.ms/new-console-template for more information
+namespace GearRatios;
-Console.WriteLine("Hello, World!");
+
+public class Program
+{
+  public async static 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 > 1 && args[1] == "part2"
+      ? puzzleSolver.SumGearRatios(input)
+      : puzzleSolver.SumPartNumbers(input);
+
+    if (args.Length > 1 && args[1] == "part2")
+    {
+      Console.WriteLine($"The sum of all gear ratios is {result}.");
+    }
+    else
+    {
+      Console.WriteLine($"The sum of all part numbers is {result}.");
+    }
+
+    return result;
+  }
+}
+
+public class PuzzleSolver
+{
+  public int SumPartNumbers(string[] schematic)
+  {
+    var allPartNumbers = new List<int>();
+
+    for (var i = 0; i < schematic.Length; i++)
+    {
+      var currentLine = Line.Parse(schematic[i]);
+      var prevLine = i > 0 ? Line.Parse(schematic[i - 1]) : null;
+      var nextLine = i < schematic.Length - 1 ? Line.Parse(schematic[i + 1]) : null;
+      var linePartNumbers = currentLine.GetPartNumbers(prevLine, nextLine);
+      allPartNumbers.AddRange(linePartNumbers);
+    }
+
+    return allPartNumbers.Sum();
+  }
+
+  public int SumGearRatios(string[] schematic)
+  {
+    var allGearRatios = new List<int>();
+
+    for (var i = 0; i < schematic.Length; i++)
+    {
+      var currentLine = Line.Parse(schematic[i]);
+      var prevLine = i > 0 ? Line.Parse(schematic[i - 1]) : null;
+      var nextLine = i < schematic.Length - 1 ? Line.Parse(schematic[i + 1]) : null;
+      var lineGearRatios = currentLine.GetGearRatios(prevLine, nextLine);
+      allGearRatios.AddRange(lineGearRatios);
+    }
+
+    return allGearRatios.Sum();
+  }
+}
+
+public class Line(
+  List<Dictionary<int, Indexes>> numbers,
+  List<Dictionary<string, Indexes>> specialCharacters
+)
+{
+  public List<Dictionary<int, Indexes>> Numbers { get; init; } = numbers;
+  public List<Dictionary<string, Indexes>> SpecialCharacters { get; init; } = specialCharacters;
+  public List<int> SpecialCharacterIndexes => SpecialCharacters.SelectMany(dict => dict.Values).Select(v => v.Start).ToList();
+
+  private bool IsGearCharacter(string character) => character == "*";
+
+  public List<int> GetGearRatios(Line? previousLine = null, Line? nextLine = null)
+  {
+    var gearRatios = new List<int>();
+    var gearCharacters = SpecialCharacters.Where(dict => dict.Keys.Any(IsGearCharacter)).ToList();
+
+    if (previousLine is not null)
+    {
+      Numbers.AddRange(previousLine.Numbers);
+    }
+
+    if (nextLine is not null)
+    {
+      Numbers.AddRange(nextLine.Numbers);
+    }
+
+    foreach (var gear in gearCharacters)
+    {
+      foreach (var (key, value) in gear)
+      {
+        var beforeGear = value.Start - 1;
+        var afterGear = value.End + 1;
+
+        var gearNumbers = Numbers
+          .Where(
+            n => n.Values.Any(
+              v =>
+                v.Start >= beforeGear && v.Start <= afterGear ||
+                v.End >= beforeGear && v.End <= afterGear
+            )
+          )
+          .SelectMany(n => n.Keys)
+          .ToList();
+
+        if (gearNumbers.Count == 2)
+        {
+          gearRatios.Add(gearNumbers.First() * gearNumbers.Last());
+        }
+      }
+    }
+
+    return gearRatios;
+  }
+
+  public List<int> GetPartNumbers(Line? previousLine = null, Line? nextLine = null)
+  {
+    var partNumbers = new List<int>();
+
+    if (previousLine is not null)
+    {
+      SpecialCharacters.AddRange(previousLine.SpecialCharacters);
+    }
+
+    if (nextLine is not null)
+    {
+      SpecialCharacters.AddRange(nextLine.SpecialCharacters);
+    }
+
+    foreach (var number in Numbers)
+    {
+      foreach (var (key, value) in number)
+      {
+        var beforeNumber = value.Start - 1;
+        var afterNumber = value.End + 1;
+
+        if (SpecialCharacterIndexes.Any(idx => idx >= beforeNumber && idx <= afterNumber))
+        {
+          partNumbers.Add(key);
+        }
+      }
+    }
+
+    return partNumbers;
+  }
+
+  public static Line Parse(string line)
+  {
+    var numbers = new List<Dictionary<int, Indexes>>();
+    var specialCharacters = new List<Dictionary<string, Indexes>>();
+
+    var number = string.Empty;
+    int? numberStart = null;
+    int? numberEnd;
+
+    for (var i = 0; i < line.Length; i++)
+    {
+      var currentCharacter = line[i];
+
+      if (char.IsDigit(currentCharacter))
+      {
+        number += line[i];
+        numberStart ??= i;
+
+        if (i == line.Length - 1)
+        {
+          numberEnd = i;
+          numbers.Add(new()
+          {
+            {
+              int.Parse(number),
+              new Indexes(numberStart.Value, numberEnd.Value)
+            }
+          });
+        }
+      }
+      else
+      {
+        if (numberStart.HasValue)
+        {
+          numberEnd = i - 1;
+          numbers.Add(new()
+          {
+            {
+              int.Parse(number),
+              new Indexes(numberStart.Value, numberEnd.Value)
+            }
+          });
+          number = string.Empty;
+          numberStart = null;
+        }
+
+        if (currentCharacter == '.')
+        {
+          continue;
+        }
+
+        specialCharacters.Add(new()
+        {
+          {
+            currentCharacter.ToString(),
+            new Indexes(i, i)
+          }
+        });
+      }
+    }
+
+    return new Line(numbers, specialCharacters);
+  }
+}
+
+public class Indexes(int start, int end)
+{
+  public int Start { get; init; } = start;
+  public int End { get; init; } = end;
+}

03/SCRATCH.md

@@ -0,0 +1,90 @@
+# Notes
+
+## Contraints
+
+- Periods don't count as special characters
+- All lines have same length
+- If not a number or period then it is a special character
+
+Each line parsed need to collect all numbers.
+
+Can't know whether a collected number is a part number until we
+have also parsed the proceeding or following line.
+
+```text
+467..114..
+...*......
+..35..633.
+......#...
+617*......
+```
+
+After parsing first line we would have `467` with start index 0 and end index 2 and `114` with start index 5 and end index 7.
+
+For 467 to be a part number it needs to have a special character at index 3 or it needs to have a special character at index 1, 2, 3, 4 on the next line.
+
+For 114 to be a part number it needs to have a special character at index 4 or index 8 or it needs to have a special character at index 4, 5, 6, 7 on the next line.
+
+Need to keep track of:
+
+- Previous line - will start as empty
+- Current line
+- Next line
+
+So you look at the current line and you parse all the numbers with their start and end index. You also parse all special characters with their index.
+
+Then you end up with something like this: currentLine
+
+```json
+{
+  "numbers": [
+    "467": {
+      "start": 0,
+      "end": 2
+    },
+    "114": {
+      "start": 5,
+      "end": 7
+    }
+  ],
+  "specialCharacters": []
+}
+```
+
+```csharp
+var currentLineString = "467..114..";
+var currentLine = new Line(currentLineString);
+
+class Line
+{
+  public List<Dictionary<int, Indexes>> Numbers { get; set; }
+  public List<Dictionary<int, Indexes>> SpecialCharacters { get; set; }
+
+  public Line(string line)
+  {
+    // parse line
+  }
+}
+
+public class Indexes
+{
+  public int Start { get; set; }
+  public int End { get; set; }
+
+  public Indexes(int start, int length)
+  {
+    Start = start;
+    End = start + length;
+  }
+}
+```
+
+Then you see if those numbers are part numbers just by checking if a special character proceeds or follows their start and end indexes.
+
+```csharp
+```
+
+If not then you need to see if there is a previous line and whether there is a special character at on the previous line that has an index that is between 1 less than the start index and 1 more than the end index.
+
+If not then you need to see if there is a next line and whether there is a special character at on the next line that has an index that is between 1 less than the start index and 1 more than the end index.
+```

AdventOfCode2023.sln

@@ -19,7 +19,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "03", "03", "{EA04152D-316A-
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "GearRatios", "03\GearRatios\GearRatios.csproj", "{F697AC19-C92D-4E2A-975A-1A16A1961133}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "GearRatios.Test", "03\GearRatios.Test\GearRatios.Test.csproj", "{FEE9253C-A56B-4735-BDB3-C62220C5B1B1}"
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "GearRatios.Tests", "03\GearRatios.Tests\GearRatios.Tests.csproj", "{FEE9253C-A56B-4735-BDB3-C62220C5B1B1}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution