From 3af6cc3233c94275de61080f340a733e964c7020 Mon Sep 17 00:00:00 2001
From: Sebastian Lindemeier <lindemeier.sebastian@bgetem.de>
Date: Thu, 11 Dec 2025 12:05:45 +0100
Subject: [PATCH] Refactor Day10 to enhance button and joltage handling,
 implement Z3 solver for Part 2 logic, and update tests accordingly

---
 AoC_2025.Tests/Day10Test.cs |  8 ++---
 AoC_2025/AoC_2025.csproj    |  4 +++
 AoC_2025/Day10.cs           | 58 ++++++++++++++++++++++++++++++-------
 3 files changed, 55 insertions(+), 15 deletions(-)

diff --git a/AoC_2025.Tests/Day10Test.cs b/AoC_2025.Tests/Day10Test.cs
index 41086b4..5dd4469 100644
--- a/AoC_2025.Tests/Day10Test.cs
+++ b/AoC_2025.Tests/Day10Test.cs
@@ -30,18 +30,18 @@ public class Day10Test
     }
     
     [Fact]
-    public void Part02_Test_equals_24()
+    public void Part02_Test_equals_33()
     {
         var actual = _sut.SolvePart2(TestInputPath);
         
-        Assert.Equal(24, actual);
+        Assert.Equal(33, actual);
     }
     
     [Fact]
-    public void Part02_Prod_equals_1568849600()
+    public void Part02_Prod_equals_19763()
     {
         var actual = _sut.SolvePart2(ProdInputPath);
         
-        Assert.Equal(1568849600, actual);
+        Assert.Equal(19763, actual);
     }
 }
\ No newline at end of file
diff --git a/AoC_2025/AoC_2025.csproj b/AoC_2025/AoC_2025.csproj
index e85e30f..678a88a 100644
--- a/AoC_2025/AoC_2025.csproj
+++ b/AoC_2025/AoC_2025.csproj
@@ -10,4 +10,8 @@
       <ProjectReference Include="..\AdvenOfCode.Contracts\AdvenOfCode.Contracts.csproj" />
     </ItemGroup>
 
+    <ItemGroup>
+      <PackageReference Include="Microsoft.Z3" Version="4.12.2" />
+    </ItemGroup>
+
 </Project>
diff --git a/AoC_2025/Day10.cs b/AoC_2025/Day10.cs
index 39a9ecf..bbd975c 100644
--- a/AoC_2025/Day10.cs
+++ b/AoC_2025/Day10.cs
@@ -5,13 +5,13 @@ using System.Data.Common;
 using System.IO;
 using System.Linq;
 using AdvenOfCode.Contracts;
+using Microsoft.Z3;
 
 namespace AoC_2025;
 
 public class Day10 : IPuzzleSolver<long>
 {
-    private static int done = 0;
-    private (uint lamps, uint[] buttons, int[] joltages)[] ParsePuzzleInput(string path)
+    private (uint lamps, (int[] buttons, uint buttonsMap)[] buttons, int[] joltages)[] ParsePuzzleInput(string path)
     {
         var puzzleInput = File.ReadAllLines(path)
             .Where(line => !string.IsNullOrWhiteSpace(line))
@@ -35,7 +35,8 @@ public class Day10 : IPuzzleSolver<long>
                 .Select(button => button[1..^1]
                     .Split(',', StringSplitOptions.RemoveEmptyEntries)
                     .Select(lampIndex => int.Parse(lampIndex))
-                    .Aggregate((uint)0L, (acc, lampIndex) => acc | ((uint)1 << lampIndex)))
+                    .ToArray())
+                .Select(lampIndexes => (lampIndexes, lampIndexes.Aggregate((uint)0L, (acc, lampIndex) => acc | ((uint)1 << lampIndex))))
                 .ToArray())
             .ToArray();
         var joltages = puzzleInput
@@ -55,19 +56,23 @@ public class Day10 : IPuzzleSolver<long>
     public long SolvePart1(string pathToPuzzleInput)
     {
         var instructions = ParsePuzzleInput(pathToPuzzleInput);
-        Console.WriteLine($"total: {instructions.Length}");
         var minCounts = instructions
-            .Select(ins => GetMinCountButtonPressesForLamps(ins.lamps, ins.buttons))
+            .Select(ins => GetMinCountButtonPressesForLamps(ins.lamps, [..ins.buttons.Select(b => b.buttonsMap)]))
             .ToArray();
         return minCounts.Sum();
     }
 
     public long SolvePart2(string pathToPuzzleInput)
     {
-        return 0;
+        var instructions = ParsePuzzleInput(pathToPuzzleInput);
+        var minCounts = instructions
+            .Select(ins => GetMinCountButtonPressesForJoltages(ins.joltages, [..ins.buttons.Select(b => b.buttons)]))
+            .ToArray();
+        var sum = minCounts.Sum();
+        return sum;
     }
 
-    private static long GetMinCountButtonPressesForLamps(uint lamps, uint[] buttons)
+    private long GetMinCountButtonPressesForLamps(uint lamps, uint[] buttons)
     {
         var presses = 0L;
         HashSet<uint> lampStates = [lamps];
@@ -79,18 +84,49 @@ public class Day10 : IPuzzleSolver<long>
                 .ToHashSet();
             presses++;
         }
-
-        var amount = Interlocked.Increment(ref done);
-        Console.WriteLine($"done: {amount}, presses: {presses}");
         
         return presses;
     }
 
-    private static uint[] GetLampStates(uint lampState, uint[] buttons)
+    private uint[] GetLampStates(uint lampState, uint[] buttons)
     {
         var states = buttons
             .Where(button => (lampState & button) > 0)
             .Select(button => lampState ^ button);
         return [..states];
     }
+
+    private long GetMinCountButtonPressesForJoltages(int[] joltages, int[][] buttons)
+    {
+        using var context = new Context();
+        var optimize = context.MkOptimize();
+        var variables = Enumerable.Range(0, buttons.Length)
+            .Select(ix => context.MkIntConst($"n{ix}"))
+            .ToArray();
+        foreach (var variable in variables)
+        {
+            optimize.Add(variable >= 0);
+        }
+
+        var zero = context.MkInt(0);
+        foreach (var (i, joltage) in joltages.Index())
+        {
+            var equation = zero + zero;
+            
+            foreach (var (b, button) in buttons.Index())
+            {
+                if(button.Contains(i))
+                    equation += variables[b];
+            }
+
+            optimize.Add(context.MkEq(equation, context.MkInt(joltage)));
+        }
+        var sumVariables = variables.Aggregate(zero + zero, (current, variable) => current + variable);
+
+        optimize.MkMinimize(sumVariables);
+        optimize.Check();
+        var answerExpression = optimize.Model.Eval(sumVariables);
+        var answer = answerExpression is IntNum number ? number.Int64 : 0;
+        return answer;
+    }
 }
\ No newline at end of file