Add Day11 implementation with puzzle-solving logic and tests

AoC_2025/Day11.cs

@@ -0,0 +1,74 @@
+using System;
+using System.Collections.Generic;
+using System.Data;
+using System.Data.Common;
+using System.IO;
+using System.Linq;
+using AdvenOfCode.Contracts;
+
+namespace AoC_2025;
+
+public class Day11 : IPuzzleSolver<long>
+{
+    private Dictionary<string, string[]> ParsePuzzleInput(string path)
+    {
+        var puzzleInput = File.ReadAllLines(path)
+            .Where(line => !string.IsNullOrWhiteSpace(line))
+            .Select(line => line.Split(':', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries))
+            .Select(line => (line[0], line[1].Split(' ', StringSplitOptions.RemoveEmptyEntries)))
+            .ToDictionary();
+            
+        return puzzleInput;
+    }
+
+    public long SolvePart1(string pathToPuzzleInput)
+    {
+        var connections = ParsePuzzleInput(pathToPuzzleInput);
+        var pathsToOut = GetAmountPaths("you", "out", connections, []);
+        return pathsToOut;
+    }
+
+    public long SolvePart2(string pathToPuzzleInput)
+    {
+        var connections = ParsePuzzleInput(pathToPuzzleInput);
+        var pathsToOut = GetAmountPathsThrough("svr", "out", ["dac", "fft"], connections, []);
+        return pathsToOut;
+    }
+
+    private long GetAmountPaths(string from, string to, Dictionary<string, string[]> paths, Dictionary<(string, string), long> memory)
+    {
+        if (from == to) return 1;
+        if (memory.TryGetValue((from, to), out var res)) return res;
+        
+        var totalAmount = 0L;
+        foreach (var path in paths[from])
+        {
+            var amount = GetAmountPaths(path, to, paths, memory);
+            memory[(path, to)] = amount;
+            totalAmount += amount;
+        }
+
+        memory[(from, to)] = totalAmount;
+        return totalAmount;
+    }
+    
+    private long GetAmountPathsThrough(string from, string to, HashSet<string> through, 
+        Dictionary<string, string[]> paths, 
+        Dictionary<(string, string), (long, HashSet<string>)> memory)
+    {
+        through.Remove(from);
+        if (from == to) return through.Count == 0 ? 1 : 0;
+        if (memory.TryGetValue((from, to), out var res) && res.Item2.SetEquals(through)) return res.Item1;
+        
+        var totalAmount = 0L;
+        foreach (var path in paths[from])
+        {
+            var amount = GetAmountPathsThrough(path, to, [..through], paths, memory);
+            memory[(path, to)] = (amount, through);
+            totalAmount += amount;
+        }
+
+        memory[(from, to)] = (totalAmount, through);
+        return totalAmount;
+    }
+}