feat(2024-07): Add day 7 part 1 with start to part 2

2026-07-13 03:03:46 +00:00 · 2024-12-07 22:52:33 +00:00
parent 3cefca16e7
commit ff92ba7e2e
3 changed files with 1041 additions and 0 deletions
@@ -0,0 +1,146 @@
+namespace AOC.Tests.Y2024;
+
+[TestFixture]
+[Parallelizable(ParallelScope.All)]
+public class Day07
+{
+    [SetUp]
+    public void Setup()
+    {
+        realData = File.ReadAllLines(Path.Combine(TestContext.CurrentContext.TestDirectory, "Y2024", "Data",
+            $"{GetThisClassName()}.dat"));
+    }
+
+    protected string GetThisClassName() { return GetType().Name; }
+    private string[] realData;
+
+    private bool CanAchieveTarget(long[] remainingNumbers, long testValue, long currentIndex, long currentTotal)
+    {
+        // Base case: if we've used all numbers, check if the total equals the test value
+        if (currentIndex == remainingNumbers.Length)
+        {
+            return currentTotal == testValue;
+        }
+
+        // Try adding the next number
+        if (CanAchieveTarget(remainingNumbers, testValue, currentIndex + 1,
+                currentTotal + remainingNumbers[currentIndex]))
+        {
+            return true;
+        }
+
+        // Try multiplying by the next number
+        if (CanAchieveTarget(remainingNumbers, testValue, currentIndex + 1,
+                currentTotal * remainingNumbers[currentIndex]))
+        {
+            return true;
+        }
+
+        // If neither operation works, return false
+        return false;
+    }
+
+    private bool CanAchieveTargetWithConcatenation(long[] remainingNumbers, long testValue, long currentIndex,
+        long currentTotal)
+    {
+        // If none of the three operations works, return false
+        return false;
+    }
+
+
+    private (bool, long) CanEquationBeTrue(string equation, bool enableConcatenation = false)
+    {
+        try
+        {
+            // Split the equation into its parts
+            string[] parts = equation.Split(": ");
+            long testValue = long.Parse(parts[0]);
+            long[] remainingNumbers = parts[1].Split(" ").Select(long.Parse).ToArray();
+
+            if (enableConcatenation)
+            {
+                bool result = CanAchieveTargetWithConcatenation(remainingNumbers, testValue, 1, remainingNumbers[0]);
+
+                return (result, testValue);
+            }
+            else
+            {
+                // Start recursing through the numbers
+                bool result = CanAchieveTarget(remainingNumbers, testValue, 1, remainingNumbers[0]);
+
+                return (result, testValue);
+            }
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine(equation, ex);
+            throw;
+        }
+    }
+
+    [TestCase(@"190: 10 19
+3267: 81 40 27
+83: 17 5
+156: 15 6
+7290: 6 8 6 15
+161011: 16 10 13
+192: 17 8 14
+21037: 9 7 18 13
+292: 11 6 16 20", 3749)]
+    [TestCase(null, 1620690235709)] // The actual answer
+    public void Part1(string? input, long? expected)
+    {
+        string[] lines = input != null ? input.Split("\n") : realData;
+
+        long result = 0;
+
+        foreach (string line in lines)
+        {
+            (bool, long) response = CanEquationBeTrue(line);
+            if (response.Item1)
+            {
+                result += response.Item2;
+            }
+        }
+
+        if (expected != null)
+        {
+            Assert.That(result, Is.EqualTo(expected.Value));
+        }
+
+        Console.WriteLine($"Part 1: {result}");
+    }
+
+    [TestCase(@"190: 10 19
+3267: 81 40 27
+83: 17 5
+156: 15 6
+7290: 6 8 6 15
+161011: 16 10 13
+192: 17 8 14
+21037: 9 7 18 13
+292: 11 6 16 20", 11387)]
+    [TestCase(null, 1783)] // The actual answer
+    public void Part2(string? input, long? expected)
+    {
+        string[] lines = input != null ? input.Split("\n") : realData;
+
+        long result = 0;
+
+        foreach (string line in lines)
+        {
+            (bool, long) response = CanEquationBeTrue(line, true);
+            if (response.Item1)
+            {
+                result += response.Item2;
+            }
+        }
+
+        if (expected != null)
+        {
+            Assert.That(result, Is.EqualTo(expected.Value));
+        }
+
+        Console.WriteLine($"Part 2: {result}");
+    }
+}