feat: solved day 13 part 1 and part 2

2024-12-14 12:58:28 -06:00
parent 46976b049c
commit abfa9e50ba
6 changed files with 312 additions and 3 deletions
@@ -0,0 +1,111 @@
+using System.Text.RegularExpressions;
+
+namespace ClawContraption;
+
+partial class Machine
+{
+  private readonly int? _maxPresses;
+  private readonly Button _buttonA;
+  private readonly Button _buttonB;
+  private readonly PrizeLocation _prizeLocation;
+  private decimal NumberOfButtonBPresses => 
+    ((_prizeLocation.Y * _buttonA.XMovement) - (_prizeLocation.X * _buttonA.YMovement)) / ((_buttonB.YMovement * _buttonA.XMovement) - (_buttonB.XMovement * _buttonA.YMovement));
+
+  private decimal NumberOfButtonAPresses =>
+    (_prizeLocation.X - (_buttonB.XMovement * NumberOfButtonBPresses)) / _buttonA.XMovement;
+
+  private bool HasSolution => CheckForSolution();
+
+  public decimal TokenCost => HasSolution ? (NumberOfButtonBPresses * 1) + (NumberOfButtonAPresses * 3) : 0;
+  
+  private Machine(Button buttonA, Button buttonB, PrizeLocation prizeLocation, int? maxPresses = null)
+  {
+    _buttonA = buttonA;
+    _buttonB = buttonB;
+    _prizeLocation = prizeLocation;
+    _maxPresses = maxPresses;
+  }
+
+  internal static Machine From(Button buttonA, Button buttonB, PrizeLocation prizeLocation, int? maxPresses) =>
+    new(buttonA, buttonB, prizeLocation, maxPresses);
+
+  public static Machine From(string[] input, int? maxPresses = null, long prizeLocationOffset = 0)
+  {
+    if (input.Length is not 3)
+    {
+      throw new ApplicationException("Input describing machine is not valid");
+    }
+
+    var buttonAInput = input[0];
+    var buttonBInput = input[1];
+    var prizeInput = input[2];
+    
+    var buttonAMatches = ButtonARegex().Match(buttonAInput);
+    var buttonBMatches = ButtonBRegex().Match(buttonBInput);
+    var prizeMatches = PrizeRegex().Match(prizeInput);
+
+    if (buttonAMatches.Groups.Count is not 3)
+    {
+      throw new ApplicationException("input for button A missing values");
+    }
+    
+    if (buttonBMatches.Groups.Count is not 3)
+    {
+      throw new ApplicationException("input for button B missing values");
+    }
+    
+    if (prizeMatches.Groups.Count is not 3)
+    {
+      throw new ApplicationException("input for prize missing values");
+    }
+
+    var buttonA = new Button(
+      int.Parse(buttonAMatches.Groups[1].Value),
+      int.Parse(buttonAMatches.Groups[2].Value)
+    );
+    
+    var buttonB = new Button(
+      int.Parse(buttonBMatches.Groups[1].Value),
+      int.Parse(buttonBMatches.Groups[2].Value)
+    );
+    
+    var prize = new PrizeLocation(
+      int.Parse(prizeMatches.Groups[1].Value) + prizeLocationOffset,
+      int.Parse(prizeMatches.Groups[2].Value) + prizeLocationOffset
+    );
+
+    return new(buttonA, buttonB, prize, maxPresses);
+  }
+
+  private bool CheckForSolution()
+  {
+    if (Math.Floor(NumberOfButtonAPresses) != NumberOfButtonAPresses)
+    {
+      return false;
+    }
+
+    if (Math.Floor(NumberOfButtonBPresses) != NumberOfButtonBPresses)
+    {
+      return false;
+    }
+
+    if (_maxPresses.HasValue && NumberOfButtonAPresses > _maxPresses)
+    {
+      return false;
+    }
+
+    if (_maxPresses.HasValue && NumberOfButtonBPresses > _maxPresses)
+    {
+      return false;
+    }
+
+    return true;
+  }
+  
+  [GeneratedRegex(@"Button A: X\+(\d+), Y\+(\d+)")]
+  private static partial Regex ButtonARegex();
+  [GeneratedRegex(@"Button B: X\+(\d+), Y\+(\d+)")]
+  private static partial Regex ButtonBRegex();
+  [GeneratedRegex(@"Prize: X=(\d+), Y=(\d+)")]
+  private static partial Regex PrizeRegex();
+}