Extract `Coordinate`, `IntegerRange` and `Coordinate3d` to new `AdventOfCode.HelperClasses` project and refactor solution for modularity and type consistency

AdventOfCode.Extensions/AdventOfCode.Extensions.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net9.0</TargetFramework>
+        <ImplicitUsings>disable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+    </PropertyGroup>
+
+</Project>

AdventOfCode.Extensions/EnumerableExtensions.cs

@@ -0,0 +1,52 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace AdventOfCode.Extensions;
+
+public static class EnumerableExtensions
+{
+    public static IEnumerable<TValue[]> Combinations<TValue>(this IEnumerable<TValue> values, int count)
+    {
+        var pool = values.ToArray();
+        var poolLength = pool.Length;
+        if (count > poolLength)
+            yield break;
+        var indices = Range(0, count).ToArray();
+        yield return GetCombination(indices, pool);
+        while (true)
+        {
+            var validIndex = false;
+            var currentIndex = 0;
+            foreach (var i in Range(0, count).Reverse())
+            {
+                currentIndex = i;
+                if (indices[i] != i + poolLength - count)
+                {
+                    validIndex = true;
+                    break;
+                }
+            }
+            if(!validIndex)
+                yield break;
+            
+            indices[currentIndex] += 1;
+            foreach (var j in Range(currentIndex + 1, count))
+            {
+                Index ix = j - 1;
+                indices[j] = indices[ix] + 1;
+            }
+
+            yield return GetCombination(indices, pool);
+        }
+
+        static TValue[] GetCombination(int[] innerIndices, TValue[] innerPool) => 
+            innerIndices.Select(i => innerPool[i]).ToArray();
+
+        static IEnumerable<int> Range(int start, int end)
+        {
+            for (var i = start; i < end; i++)
+                yield return i;
+        }
+    }
+}

AdventOfCode.HelperClasses/AdventOfCode.HelperClasses.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net9.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+    </PropertyGroup>
+
+</Project>

AdventOfCode.HelperClasses/Coordinate.cs

@@ -0,0 +1,25 @@
+namespace AdventOfCode.HelperClasses;
+
+public record Coordinate(long X, long Y)
+{
+    public double GetEuclidianDistance(Coordinate other) =>
+        Math.Sqrt((X - other.X) * (X - other.X) + (Y - other.Y) * (Y - other.Y));
+
+    public static double GetEuclidianDistance(Coordinate a, Coordinate b) =>
+        Math.Sqrt((a.X - b.X) * (a.X - b.X) + (a.Y - b.Y) * (a.Y - b.Y));
+    
+    public static Coordinate operator +(Coordinate left, Coordinate right) => 
+        new(left.X + right.X, left.Y + right.Y);
+}
+
+public record Coordinate3d(long X, long Y, long Z)
+{
+    public double GetEuclidianDistance(Coordinate3d other) =>
+        Math.Sqrt((X - other.X) * (X - other.X) + (Y - other.Y) * (Y - other.Y) + (Z - other.Z) * (Z - other.Z));
+
+    public static double GetEuclidianDistance(Coordinate3d a, Coordinate3d b) =>
+        Math.Sqrt((a.X - b.X) * (a.X - b.X) + (a.Y - b.Y) * (a.Y - b.Y) + (a.Z - b.Z) * (a.Z - b.Z));
+    
+    public static Coordinate3d operator +(Coordinate3d left, Coordinate3d right) => 
+        new(left.X + right.X, left.Y + right.Y, left.Z + right.Z);
+}

AdventOfCode.HelperClasses/IntArrayEqualityComparer.cs

@@ -0,0 +1,24 @@
+namespace AdventOfCode.HelperClasses;
+
+public class IntArrayEqualityComparer : IEqualityComparer<int[]>
+{
+    public bool Equals(int[]? x, int[]? y)
+    {
+        if (x is null || y is null || x.Length != y.Length) return false;
+
+        return !x.Where((t, i) => t != y[i]).Any();
+    }
+
+    public int GetHashCode(int[] obj)
+    {
+        var result = 17;
+        foreach (var t in obj)
+        {
+            unchecked
+            {
+                result = result * 23 + t;
+            }
+        }
+        return result;
+    }
+}

AdventOfCode.HelperClasses/IntegerRange.cs

@@ -0,0 +1,28 @@
+namespace AdventOfCode.HelperClasses;
+
+public record IntegerRange(long start, long end)
+{
+    public long Count() => end - start + 1;
+
+    public bool Contains(long number) => start <= number && end >= number;
+
+    public bool TryCombine(IntegerRange other, out IntegerRange combined)
+    {
+        if (Contains(other.start))
+        {
+            var isEndInRange = Contains(other.end);
+            combined = isEndInRange ? this : this with {end = other.end};
+            return true;
+        }
+        
+        if (other.Contains(start))
+        {
+            var isEndInRange = other.Contains(end);
+            combined = isEndInRange ? other : other with {end = end};
+            return true;
+        }
+
+        combined = this;
+        return false;
+    }
+}

AdventOfCode.sln

@@ -10,6 +10,10 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "AoC_2025.Runner", "AoC_2025
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "AdvenOfCode.Contracts", "AdvenOfCode.Contracts\AdvenOfCode.Contracts.csproj", "{0249A329-D5C1-4699-88BE-A668B362432E}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "AdventOfCode.Extensions", "AdventOfCode.Extensions\AdventOfCode.Extensions.csproj", "{1466A0F6-7C88-47FF-B8F8-FF30368E26DC}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "AdventOfCode.HelperClasses", "AdventOfCode.HelperClasses\AdventOfCode.HelperClasses.csproj", "{D47175BB-5AD6-43A8-9287-FF5E6F1816E3}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -32,6 +36,14 @@ Global
 		{0249A329-D5C1-4699-88BE-A668B362432E}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{0249A329-D5C1-4699-88BE-A668B362432E}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{0249A329-D5C1-4699-88BE-A668B362432E}.Release|Any CPU.Build.0 = Release|Any CPU
+		{1466A0F6-7C88-47FF-B8F8-FF30368E26DC}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{1466A0F6-7C88-47FF-B8F8-FF30368E26DC}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{1466A0F6-7C88-47FF-B8F8-FF30368E26DC}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{1466A0F6-7C88-47FF-B8F8-FF30368E26DC}.Release|Any CPU.Build.0 = Release|Any CPU
+		{D47175BB-5AD6-43A8-9287-FF5E6F1816E3}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{D47175BB-5AD6-43A8-9287-FF5E6F1816E3}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{D47175BB-5AD6-43A8-9287-FF5E6F1816E3}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{D47175BB-5AD6-43A8-9287-FF5E6F1816E3}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(NestedProjects) = preSolution
 		{4F395AE3-DABB-4546-A4D0-5A62425FE168} = {05EBAA1C-B33B-4AFE-8635-A58D7CA509A7}

AoC_2025/AoC_2025.csproj

@@ -8,6 +8,8 @@
 
     <ItemGroup>
       <ProjectReference Include="..\AdvenOfCode.Contracts\AdvenOfCode.Contracts.csproj" />
+      <ProjectReference Include="..\AdventOfCode.Extensions\AdventOfCode.Extensions.csproj" />
+      <ProjectReference Include="..\AdventOfCode.HelperClasses\AdventOfCode.HelperClasses.csproj" />
     </ItemGroup>
 
     <ItemGroup>

AoC_2025/Day01.cs

@@ -1,7 +1,4 @@
-using System;
+using AdvenOfCode.Contracts;
-using System.IO;
-using System.Linq;
-using AdvenOfCode.Contracts;
 
 namespace AoC_2025;
 

AoC_2025/Day03.cs

@@ -1,7 +1,4 @@
-using System;
+using AdvenOfCode.Contracts;
-using System.IO;
-using System.Linq;
-using AdvenOfCode.Contracts;
 
 namespace AoC_2025;
 

AoC_2025/Day04.cs

@@ -1,8 +1,5 @@
-using System.Collections.Generic;
+using AdvenOfCode.Contracts;
-using System.IO;
+using AdventOfCode.HelperClasses;
-using System.Linq;
-using AdvenOfCode.Contracts;
-using Coordinate = (int x, int y);
 
 namespace AoC_2025;
 
@@ -64,7 +61,7 @@ public class Day04 : IPuzzleSolver<long>
     {
         var indexedCharacters = gridLine.Index();
         var validRolls = indexedCharacters.Where(tuple => tuple.Item == '@');
-        var rollCoordinates = validRolls.Select(tuple => (xIndex, tuple.Index));
+        var rollCoordinates = validRolls.Select(tuple => new Coordinate(xIndex, tuple.Index));
         return rollCoordinates;
     }
 
@@ -79,12 +76,12 @@ public class Day04 : IPuzzleSolver<long>
     {
         Coordinate[] neighbourDirections =
         [
-            (-1, -1), (-1, 0), (-1, 1),
+            new(-1, -1), new(-1, 0), new(-1, 1),
-            (0, -1),               (0, 1),
+            new(0, -1),              new(0, 1),
-            (1, -1),  (1, 0),  (1, 1),
+            new(1, -1),  new(1, 0),  new(1, 1),
         ];
         var possibleNeighbours = neighbourDirections
-            .Select(direction => (coordinate.x + direction.x, coordinate.y + direction.y));
+            .Select(direction => coordinate + direction);
         var actualNeighbours = possibleNeighbours
             .Where(coord => coordinates.Contains(coord))
             .ToArray();

AoC_2025/Day05.cs

@@ -1,8 +1,5 @@
-using System.Collections.Generic;
+using AdvenOfCode.Contracts;
-using System.IO;
+using AdventOfCode.HelperClasses;
-using System.Linq;
-using AdvenOfCode.Contracts;
-using Range = (long from, long to);
 
 namespace AoC_2025;
 
@@ -52,54 +49,49 @@ public class Day05 : IPuzzleSolver<long>
         return parsedIds;
     }
 
-    private Range[] ParseRanges(IEnumerable<string> ranges)
+    private IntegerRange[] ParseRanges(IEnumerable<string> ranges)
     {
         return ranges.Select(range =>
         {
             var split = range.Split('-', StringSplitOptions.RemoveEmptyEntries);
-            return (long.Parse(split[0]), long.Parse(split[1]));
+            return new IntegerRange(long.Parse(split[0]), long.Parse(split[1]));
         })
-        .OrderBy(range => range.Item1)
+        .OrderBy(range => range.start)
-        .ThenBy(range => range.Item2)
+        .ThenBy(range => range.end)
         .ToArray();
     }
     
-    private IEnumerable<long> FilterFreshIds(IEnumerable<long> ids, Range[] freshIdRanges)
+    private IEnumerable<long> FilterFreshIds(IEnumerable<long> ids, IntegerRange[] freshIdRanges)
     {
         var freshIds = ids.Where(id => IsIdInRanges(id, freshIdRanges));
         return freshIds;
     }
 
-    private bool IsIdInRanges(long id, IEnumerable<Range> ranges)
+    private bool IsIdInRanges(long id, IEnumerable<IntegerRange> ranges)
     {
-        return ranges.Any(range => IsIdInRange(id, range));
+        return ranges.Any(range => range.Contains(id));
-    }
-    
-    private bool IsIdInRange(long id, Range range)
-    {
-        return range.from <= id && range.to >= id;
     }
 
-    private long SumIdsInRanges(IEnumerable<Range> ranges)
+    private long SumIdsInRanges(IEnumerable<IntegerRange> ranges)
     {
         var sumFreshIds = 0L;
         var highestSeenId = -1L;
         foreach (var range in ranges)
         {
-            var lowestNewId = Math.Max(highestSeenId + 1, range.from);
+            var lowestNewId = Math.Max(highestSeenId + 1, range.start);
-            highestSeenId = Math.Max(highestSeenId, range.to);
+            highestSeenId = Math.Max(highestSeenId, range.end);
             sumFreshIds += Math.Max(0, highestSeenId - lowestNewId + 1);
         }
 
         return sumFreshIds;
     }
 
-    private List<Range> CombineOverlappingRanges(Range[] ranges)
+    private List<IntegerRange> CombineOverlappingRanges(IntegerRange[] ranges)
     {
-        var optimizedRanges = new List<Range>(ranges.Length) { ranges[0] };
+        var optimizedRanges = new List<IntegerRange>(ranges.Length) { ranges[0] };
         foreach (var range in ranges)
         {
-            if (TryCombineRanges(optimizedRanges[^1], range, out var combined))
+            if (optimizedRanges[^1].TryCombine(range, out var combined))
             {
                 optimizedRanges[^1] = combined;
             }
@@ -111,29 +103,10 @@ public class Day05 : IPuzzleSolver<long>
 
         return optimizedRanges;
     }
-
-    private bool TryCombineRanges(Range first, Range second, out Range combined)
-    {
-        if (IsIdInRange(second.from, first))
-        {
-            var isEndInRange = IsIdInRange(second.to, first);
-            combined = isEndInRange ? first : (first.from, second.to);
-            return true;
-        }
-        // if (IsIdInRange(first.from, second))
-        // {
-        //     var isEndInRange = IsIdInRange(first.to, second);
-        //     combined = isEndInRange ? second : (second.from, first.to);
-        //     return true;
-        // }
-
-        combined = first;
-        return false;
-    }
     
-    private static IEnumerable<long> CountIdsInRanges(IEnumerable<Range> combinedRanges)
+    private static IEnumerable<long> CountIdsInRanges(IEnumerable<IntegerRange> combinedRanges)
     {
-        var countIdsInRanges = combinedRanges.Select(range => range.to - range.from + 1);
+        var countIdsInRanges = combinedRanges.Select(range => range.Count());
         return countIdsInRanges;
     }
 }

AoC_2025/Day06.cs

@@ -1,8 +1,4 @@
-using System.Collections.Generic;
+using AdvenOfCode.Contracts;
-using System.Data.Common;
-using System.IO;
-using System.Linq;
-using AdvenOfCode.Contracts;
 
 namespace AoC_2025;
 

AoC_2025/Day07.cs

@@ -1,9 +1,5 @@
-using System.Collections.Generic;
+using AdvenOfCode.Contracts;
-using System.Data.Common;
+using AdventOfCode.HelperClasses;
-using System.IO;
-using System.Linq;
-using AdvenOfCode.Contracts;
-using Coordinate = (int x, int y);
 
 namespace AoC_2025;
 
@@ -42,7 +38,7 @@ public class Day07 : IPuzzleSolver<long>
 
     private Coordinate GetStart(string[] grid)
     {
-        return (0, grid[0].IndexOf('S'));
+        return new Coordinate(0, grid[0].IndexOf('S'));
     }
 
     private long TraverseGridAndCountSplitters(string[] grid, Coordinate start)
@@ -53,18 +49,18 @@ public class Day07 : IPuzzleSolver<long>
         var splittersHit = 0L;
         while (seen.TryDequeue(out var current))
         {
-            if (current.x >= grid.Length) continue;
+            if (current.X >= grid.Length) continue;
-            if (current.y >= grid[0].Length || current.y < 0) continue;
+            if (current.Y >= grid[0].Length || current.Y < 0) continue;
 
-            if (grid[current.x][current.y] == '^')
+            if (grid[(int)current.X][(int)current.Y] == '^')
             {
                 splittersHit++;
-                CheckAndEnqueueIfNotVisited((current.x, current.y - 1));
+                CheckAndEnqueueIfNotVisited(current with {Y = current.Y - 1});
-                CheckAndEnqueueIfNotVisited((current.x, current.y + 1));
+                CheckAndEnqueueIfNotVisited(current with {Y = current.Y + 1});
             }
             else
             {
-                CheckAndEnqueueIfNotVisited((current.x + 1, current.y));
+                CheckAndEnqueueIfNotVisited(current with {X = current.X + 1});
             }
         }
 
@@ -79,21 +75,21 @@ public class Day07 : IPuzzleSolver<long>
     // Dictionary only for memoization
     private long GetTimelinesCountRecursive(string[] grid, Coordinate current, Dictionary<Coordinate, long> memory)
     {
-        if (current.x >= grid.Length)
+        if (current.X >= grid.Length)
         {
             return 1;
         }
         if(memory.TryGetValue(current, out var count)) return count;
 
-        if (grid[current.x][current.y] == '^')
+        if (grid[(int)current.X][(int)current.Y] == '^')
         {
-            var resLeft = GetTimelinesCountRecursive(grid, (current.x, current.y - 1), memory);
+            var resLeft = GetTimelinesCountRecursive(grid, current with {Y = current.Y - 1}, memory);
-            var resRight = GetTimelinesCountRecursive(grid, (current.x, current.y + 1), memory);
+            var resRight = GetTimelinesCountRecursive(grid, current with {Y = current.Y + 1}, memory);
             memory[current] = resLeft + resRight;
             return resLeft + resRight;
         }
         
-        var res = GetTimelinesCountRecursive(grid, (current.x + 1, current.y), memory);
+        var res = GetTimelinesCountRecursive(grid, current with {X = current.X + 1}, memory);
         memory[current] = res;
         return res;
     }

AoC_2025/Day08.cs

@@ -1,10 +1,6 @@
-using System;
+using AdvenOfCode.Contracts;
-using System.Collections.Generic;
+using AdventOfCode.Extensions;
-using System.Data.Common;
+using AdventOfCode.HelperClasses;
-using System.IO;
-using System.Linq;
-using AdvenOfCode.Contracts;
-using Coordinate = (long x, long y, long z);
 
 namespace AoC_2025;
 
@@ -15,12 +11,12 @@ public class Day08 : IPuzzleSolver<long>
     {
         _amountToConnect = amountToConnect;
     }
-    private Coordinate[] ParsePuzzleInput(string path)
+    private Coordinate3d[] ParsePuzzleInput(string path)
     {
         var puzzleInput = File.ReadAllLines(path)
             .Where(line => !string.IsNullOrWhiteSpace(line))
             .Select(line => line.Split(',', StringSplitOptions.RemoveEmptyEntries).Select(str => long.Parse(str)).ToArray())
-            .Select(numbers => (numbers[0], numbers[1], numbers[2]))
+            .Select(numbers => new Coordinate3d(numbers[0], numbers[1], numbers[2]))
             .ToArray();
         return puzzleInput;
     }
@@ -41,16 +37,16 @@ public class Day08 : IPuzzleSolver<long>
         var jBoxPairs = GetAllCombinationsSortedByDistance(jBoxes);
         var circuits = CreateCircuits(jBoxes);
         var lastConnected = LastCombinedConnectAllCircuits(circuits, jBoxPairs);
-        return lastConnected.a.x * lastConnected.b.x;
+        return lastConnected.a.X * lastConnected.b.X;
     }
     
-    private List<HashSet<Coordinate>> CreateCircuits(IEnumerable<Coordinate> jBoxes)
+    private List<HashSet<Coordinate3d>> CreateCircuits(IEnumerable<Coordinate3d> jBoxes)
     {
-        return jBoxes.Select(p => new HashSet<Coordinate> { p }).ToList();
+        return jBoxes.Select(p => new HashSet<Coordinate3d> { p }).ToList();
     }
     
-    private List<HashSet<Coordinate>> CombineCircuits(List<HashSet<Coordinate>> circuits,
+    private List<HashSet<Coordinate3d>> CombineCircuits(List<HashSet<Coordinate3d>> circuits,
-        IEnumerable<(Coordinate boxA, Coordinate boxB)> jBoxPairs, int amountToConnect)
+        IEnumerable<(Coordinate3d boxA, Coordinate3d boxB)> jBoxPairs, int amountToConnect)
     {
         circuits = jBoxPairs
             .Take(amountToConnect)
@@ -58,8 +54,8 @@ public class Day08 : IPuzzleSolver<long>
         return circuits;
     }
 
-    private (Coordinate a, Coordinate b) LastCombinedConnectAllCircuits(List<HashSet<Coordinate>> circuits,
+    private (Coordinate3d a, Coordinate3d b) LastCombinedConnectAllCircuits(List<HashSet<Coordinate3d>> circuits,
-        IEnumerable<(Coordinate boxA, Coordinate boxB)> jBoxPairs)
+        IEnumerable<(Coordinate3d boxA, Coordinate3d boxB)> jBoxPairs)
     {
         foreach (var jBoxPair in jBoxPairs)
         {
@@ -67,15 +63,10 @@ public class Day08 : IPuzzleSolver<long>
             if(circuits.Count <= 1)
                 return jBoxPair;
         }
-        return ((0,0,0), (0,0,0));
+        return (new(0,0,0), new(0,0,0));
     }
 
-    private long GetDistance(Coordinate a, Coordinate b)
+    private List<HashSet<Coordinate3d>> ConnectJBoxes(Coordinate3d a, Coordinate3d b, List<HashSet<Coordinate3d>> circuits)
-    {
-        return (a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y) + (a.z - b.z) * (a.z - b.z);
-    }
-
-    private List<HashSet<Coordinate>> ConnectJBoxes(Coordinate a, Coordinate b, List<HashSet<Coordinate>> circuits)
     {
         var circuitToAddBTo = circuits.First(circuit => circuit.Contains(a));
         var circuitToAddATo = circuits.First(circuit => circuit.Contains(b));
@@ -90,25 +81,15 @@ public class Day08 : IPuzzleSolver<long>
         return circuits;
     }
 
-    private IEnumerable<(Coordinate boxA, Coordinate boxB)> GetAllCombinationsSortedByDistance(IEnumerable<Coordinate> jBoxes)
+    private IEnumerable<(Coordinate3d boxA, Coordinate3d boxB)> GetAllCombinationsSortedByDistance(IEnumerable<Coordinate3d> jBoxes)
     {
-        var combinations = Combinations(jBoxes)
+        var combinations = jBoxes.Combinations(2)
-            .OrderBy(x => GetDistance(x.a, x.b));
+            .Select(x => (a: x[0], b: x[1]))
+            .OrderBy(x => Coordinate3d.GetEuclidianDistance(x.a, x.b));
         return combinations;
     }
-
-    private IEnumerable<(TValue a, TValue b)> Combinations<TValue>(IEnumerable<TValue> values)
-    {
-        var enumeratedValues = values.Index().ToArray();
-        var pairs = 
-            from a in enumeratedValues
-            from b in enumeratedValues
-            where a.Index < b.Index
-            select (a.Item, b.Item);
-        return pairs;
-    }
     
-    private long MultiplyLargestCircuitLength(List<HashSet<Coordinate>> circuits, int amountMultiply)
+    private long MultiplyLargestCircuitLength(List<HashSet<Coordinate3d>> circuits, int amountMultiply)
     {
         return circuits
             .Select(circuit => (long)circuit.Count)

AoC_2025/Day09.cs

@@ -1,10 +1,6 @@
-using System;
+using AdvenOfCode.Contracts;
-using System.Collections.Generic;
+using AdventOfCode.Extensions;
-using System.Data.Common;
+using AdventOfCode.HelperClasses;
-using System.IO;
-using System.Linq;
-using AdvenOfCode.Contracts;
-using Coordinate = (long x, long y);
 using CoordinatePair = (long minX, long minY, long maxX, long maxY);
 
 namespace AoC_2025;
@@ -16,7 +12,7 @@ public class Day09 : IPuzzleSolver<long>
         var puzzleInput = File.ReadAllLines(path)
             .Where(line => !string.IsNullOrWhiteSpace(line))
             .Select(line => line.Split(',', StringSplitOptions.RemoveEmptyEntries).Select(str => long.Parse(str)).ToArray())
-            .Select(numbers => (numbers[0], numbers[1]))
+            .Select(numbers => new Coordinate(numbers[0], numbers[1]))
             .ToArray();
         return puzzleInput;
     }
@@ -42,7 +38,7 @@ public class Day09 : IPuzzleSolver<long>
     private IOrderedEnumerable<long> GetOrderedAreas(IEnumerable<CoordinatePair> containedRectangles)
     {
         return containedRectangles
-            .Select(rectangle => GetArea((rectangle.maxX, rectangle.maxY), (rectangle.minX, rectangle.minY)))
+            .Select(rectangle => GetArea(new Coordinate(rectangle.maxX, rectangle.maxY), new Coordinate(rectangle.minX, rectangle.minY)))
             .OrderDescending();
     }
 
@@ -54,7 +50,7 @@ public class Day09 : IPuzzleSolver<long>
 
     private IEnumerable<CoordinatePair> GetAllPossibleRectanglesAsPairs(Coordinate[] redTiles)
     {
-        return Combinations(redTiles).Select(x => AsPair(x.a, x.b));
+        return redTiles.Combinations(2).Select(x => AsPair(x[0], x[1]));
     }
 
     private CoordinatePair[] GetBordersAsPairs(Coordinate[] redTiles)
@@ -70,7 +66,7 @@ public class Day09 : IPuzzleSolver<long>
 
     private CoordinatePair AsPair(Coordinate a, Coordinate b)
     {
-        return (Math.Min(a.x, b.x), Math.Min(a.y, b.y), Math.Max(a.x, b.x), Math.Max(a.y, b.y));
+        return (Math.Min(a.X, b.X), Math.Min(a.Y, b.Y), Math.Max(a.X, b.X), Math.Max(a.Y, b.Y));
     }
 
     private bool RectangleCrossesBorder(CoordinatePair rectangle, CoordinatePair borderSegment)
@@ -81,18 +77,7 @@ public class Day09 : IPuzzleSolver<long>
 
     private long GetArea(Coordinate tileA, Coordinate tileB)
     {
-        return (Math.Abs(tileA.x - tileB.x) + 1) * (Math.Abs(tileA.y - tileB.y) + 1);
+        return (Math.Abs(tileA.X - tileB.X) + 1) * (Math.Abs(tileA.Y - tileB.Y) + 1);
-    }
-
-    private IEnumerable<(TValue a, TValue b)> Combinations<TValue>(IEnumerable<TValue> values)
-    {
-        var enumeratedValues = values.Index().ToArray();
-        var pairs = 
-            from a in enumeratedValues
-            from b in enumeratedValues
-            where a.Index < b.Index
-            select (a.Item, b.Item);
-        return pairs;
     }
 
     private IEnumerable<(Coordinate a, Coordinate b)> GetBorders(Coordinate[] tiles)

AoC_2025/Day10.cs

@@ -1,18 +1,14 @@
-using System;
+using System.Data;
-using System.Collections;
-using System.Collections.Generic;
-using System.Data;
-using System.Data.Common;
-using System.IO;
-using System.Linq;
 using AdvenOfCode.Contracts;
+using AdventOfCode.Extensions;
+using AdventOfCode.HelperClasses;
 using Microsoft.Z3;
 
 namespace AoC_2025;
 
 public class Day10 : IPuzzleSolver<long>
 {
-    private (uint lamps, uint[] buttons, int[] joltages)[] ParsePuzzleInput(string path)
+    private (uint lamps, uint[] buttons)[] ParsePuzzleInput(string path)
     {
         var puzzleInput = File.ReadAllLines(path)
             .Where(line => !string.IsNullOrWhiteSpace(line))
@@ -40,16 +36,8 @@ public class Day10 : IPuzzleSolver<long>
                 .Select(lampIndexes => lampIndexes.Aggregate((uint)0L, (acc, lampIndex) => acc | ((uint)1 << lampIndex)))
                 .ToArray())
             .ToArray();
-        var joltages = puzzleInput
-            .Select(input => input.joltages)
-            .Select(joltage => joltage
-                .Split(',', StringSplitOptions.RemoveEmptyEntries)
-                .Select(jolt => int.Parse(jolt))
-                .ToArray())
-            .ToArray();
         var res = lamps
             .Zip(buttons, (lamp, button) => (lamp, button))
-            .Zip(joltages, (bl, joltage) => (bl.lamp, bl.button, joltage))
             .ToArray();
         return res;
     }
@@ -214,7 +202,7 @@ public class Day10 : IPuzzleSolver<long>
         yield return ([..Enumerable.Repeat(0, patternLength)], 0);
         for (var i = 1; i <= buttons.Length; i++)
         {
-            foreach (var buttonPattern in Combinations(buttons, i))
+            foreach (var buttonPattern in buttons.Combinations(i))
             {
                 var joltageLevels = GetJoltageLevelsForButtonPattern(patternLength, buttonPattern);
                 yield return (joltageLevels, buttonPattern.Length);
@@ -271,71 +259,4 @@ public class Day10 : IPuzzleSolver<long>
         var answer = answerExpression is IntNum number ? number.Int64 : 0;
         return answer;
     }
-    
-    private IEnumerable<TValue[]> Combinations<TValue>(IEnumerable<TValue> values, int count)
-    {
-        var pool = values.ToArray();
-        var poolLength = pool.Length;
-        if (count > poolLength)
-            yield break;
-        var indices = Range(0, count).ToArray();
-        yield return GetCombination(indices, pool);
-        while (true)
-        {
-            var validIndex = false;
-            var currentIndex = 0;
-            foreach (var i in Range(0, count).Reverse())
-            {
-                currentIndex = i;
-                if (indices[i] != i + poolLength - count)
-                {
-                    validIndex = true;
-                    break;
-                }
-            }
-            if(!validIndex)
-                yield break;
-            
-            indices[currentIndex] += 1;
-            foreach (var j in Range(currentIndex + 1, count))
-            {
-                Index ix = j - 1;
-                indices[j] = indices[ix] + 1;
-            }
-
-            yield return GetCombination(indices, pool);
-        }
-
-        static TValue[] GetCombination(int[] innerIndices, TValue[] innerPool) => 
-            innerIndices.Select(i => innerPool[i]).ToArray();
-
-        static IEnumerable<int> Range(int start, int end)
-        {
-            for (var i = start; i < end; i++)
-                yield return i;
-        }
-    }
-}
-
-public class IntArrayEqualityComparer : IEqualityComparer<int[]>
-{
-    public bool Equals(int[]? x, int[]? y)
-    {
-        if (x is null || y is null || x.Length != y.Length) return false;
-
-        return !x.Where((t, i) => t != y[i]).Any();
-    }
-
-    public int GetHashCode(int[] obj)
-    {
-        var result = 17;
-        foreach (var t in obj)
-        {
-            unchecked
-            {
-                result = result * 23 + t;
-            }
-        }
-        return result;
-    }
 }

AoC_2025/Day11.cs

@@ -1,10 +1,4 @@
-using System;
+using AdvenOfCode.Contracts;
-using System.Collections.Generic;
-using System.Data;
-using System.Data.Common;
-using System.IO;
-using System.Linq;
-using AdvenOfCode.Contracts;
 
 namespace AoC_2025;
 

AoC_2025/Day12.cs

@@ -1,10 +1,4 @@
-using System;
+using AdvenOfCode.Contracts;
-using System.Collections.Generic;
-using System.Data;
-using System.Data.Common;
-using System.IO;
-using System.Linq;
-using AdvenOfCode.Contracts;
 
 namespace AoC_2025;