feat: solve part 1 of puzzle 3

2023-12-04 10:32:14 -06:00
parent d50b7c75ca
commit 9f2ccdf17f
6 changed files with 250 additions and 13 deletions
@@ -1,2 +1,95 @@
-// See https://aka.ms/new-console-template for more information
-Console.WriteLine("Hello, World!");
+namespace Scratchcards;
+
+public class Program
+{
+  public static async Task<int> Main(string[] args)
+  {
+    if (args.Length is 0)
+    {
+      Console.WriteLine("Please provide a path to the input file.");
+      return -1;
+    }
+
+    if (File.Exists(args[0]) is false)
+    {
+      Console.WriteLine("The provided file does not exist.");
+      return -2;
+    }
+
+    var puzzleSolver = new PuzzleSolver();
+
+    var input = await File.ReadAllLinesAsync(args[0]);
+    var result = puzzleSolver.SumCardValues(input);
+
+    Console.WriteLine($"The sum of all card values is {result}.");
+
+    return result;
+  }
+}
+
+public class PuzzleSolver
+{
+  public int SumCardValues(string[] cards) => cards
+    .Select(Card.Parse)
+    .Sum(c => c.GetCardValue());
+}
+
+public class Card(
+  int id,
+  List<int> winningNumbers,
+  List<int> numbers
+)
+{
+  public int Id { get; init; } = id;
+  public List<int> WinningNumbers { get; init; } = winningNumbers;
+  public List<int> Numbers { get; init; } = numbers;
+
+  public int GetCardValue()
+  {
+    var commonNumbers = WinningNumbers.Intersect(Numbers).ToList();
+
+    return commonNumbers.Count is 1
+      ? 1
+      : (int)Math.Pow(2, commonNumbers.Count - 1);
+  }
+
+  public static Card Parse(string input)
+  {
+    var parts = input.Split(':');
+    var cardId = int.Parse(
+      parts[0].Split(
+        ' ',
+        StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries
+      )[1]
+    );
+
+    var numberStrings = parts[1].Trim();
+    var numberParts = numberStrings
+      .Split('|')
+      .Select(s => s.Trim())
+      .ToArray();
+
+    var winningNumbersString = numberParts[0];
+    var numbersString = numberParts[1];
+
+    var winningNumbers = winningNumbersString
+      .Split(
+        ' ',
+        StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries
+      )
+      .Select(s => s.Trim())
+      .Select(int.Parse)
+      .ToList();
+
+    var numbers = numbersString
+      .Split(
+        ' ',
+        StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries
+      )
+      .Select(s => s.Trim())
+      .Select(int.Parse)
+      .ToList();
+
+    return new Card(cardId, winningNumbers, numbers);
+  }
+}