Merge pull request #18 from MartinZikmund/feature/aoc2024-day17

AoC 2024 Day 17 Solutions

src/AdventOfCode.Puzzles/2024/17/Part1/Part1.cs

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+namespace AdventOfCode.Puzzles._2024._17.Part1;
+
+public partial class Part1 : IPuzzleSolution
+{
+    public async Task<string> SolveAsync(StreamReader inputReader)
+    {
+        return Execute(47792830, 0, 0);
+    }
+
+    private string Execute(long a, long b, long c)
+    {
+        StringBuilder output = new();
+
+        do
+        {
+            b = a % 8;
+            b = b ^ 5;
+            c = a / (long)Math.Pow(2, b);
+            b = b ^ 6;
+            b = b ^ c;
+            output.Append((b % 8).ToString() + ",");
+            a = a / 8;
+        } while (a != 0);
+
+        return output.Remove(output.Length - 1, 1).ToString();
+    }
+}

src/AdventOfCode.Puzzles/2024/17/Part2/Part2.cs

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+using System.Xml;
+
+namespace AdventOfCode.Puzzles._2024._17.Part2;
+
+public partial class Part2 : IPuzzleSolution
+{
+    private ulong _best = ulong.MaxValue;
+    private string _expectedOutput = "2415751643550330";
+
+    public async Task<string> SolveAsync(StreamReader inputReader)
+    {
+        // 2,4,1,5,7,5,1,6,4,3,5,5,0,3,3,0
+
+        // A0 = 0-7
+        // A1 = A0 * 8 - A0 * 8 + 7
+
+        Solve(0UL, _expectedOutput.Length - 1);
+        var output = Execute(107416732707226);
+        return _best.ToString();
+    }
+
+    private void Solve(ulong currentA, int index)
+    {
+        if (index == -1)
+        {
+            _best = Math.Min(_best, currentA);
+            return;
+        }
+
+        var next = _expectedOutput[index];
+        for (int remainder = 0; remainder < 8; remainder++)
+        {
+            var nextA = currentA * 8 + (ulong)remainder;
+            var result = Execute(nextA);
+            if (_expectedOutput.EndsWith(result))
+            {
+                Solve(nextA, index - 1);
+            }
+        }
+    }
+
+    private string Execute(ulong a)
+    {
+        StringBuilder output = new();
+        do
+        {
+            ulong b = a % 8;
+            b = b ^ 5;
+            ulong c = a / (ulong)Math.Pow(2, b);
+            b = b ^ 6;
+            b = b ^ c;
+            output.Append((b % 8).ToString());
+            a = a / 8;
+        } while (a != 0);
+
+        return output.ToString();
+    }
+}

src/AdventOfCode.Puzzles/2024/17/TestData.txt

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+#################
+#...#...#...#..E#
+#.#.#.#.#.#.#.#.#
+#.#.#.#...#...#.#
+#.#.#.#.###.#.#.#
+#...#.#.#.....#.#
+#.#.#.#.#.#####.#
+#.#...#.#.#.....#
+#.#.#####.#.###.#
+#.#.#.......#...#
+#.#.###.#####.###
+#.#.#...#.....#.#
+#.#.#.#####.###.#
+#.#.#.........#.#
+#.#.#.#########.#
+#S#.............#
+#################