docs: add xml comments

04/Scratchcards/Program.cs

@@ -19,40 +19,116 @@ public class Program
     var puzzleSolver = new PuzzleSolver();
 
     var input = await File.ReadAllLinesAsync(args[0]);
-    var result = puzzleSolver.SumCardValues(input);
+    var result = args.Length is 2 && args[1] == "part2"
+      ? puzzleSolver.GetTotalCardCount(input)
+      : puzzleSolver.SumCardValues(input);
 
-    Console.WriteLine($"The sum of all card values is {result}.");
+    if (args.Length is 2 && args[1] == "part2")
+    {
+      Console.WriteLine($"The total number of cards is {result}.");
+    }
+    else
+    {
+      Console.WriteLine($"The total value of the cards is {result}.");
+    }
 
     return result;
   }
 }
 
+/// <summary>
+/// Solves the puzzle.
+/// </summary>
 public class PuzzleSolver
 {
+  /// <summary>
+  /// Sums the value of the cards.
+  /// </summary>
+  /// <param name="cards">The cards.</param>
+  /// <returns>The sum of the cards.</returns>
   public int SumCardValues(string[] cards) => cards
     .Select(Card.Parse)
     .Sum(c => c.GetCardValue());
+
+  /// <summary>
+  /// Gets the total number of cards.
+  /// </summary>
+  /// <param name="cards">The cards.</param>
+  /// <returns>The total number of cards.</returns>
+  public int GetTotalCardCount(string[] cards)
+  {
+    var cardStringsToProcess = new List<string>(cards);
+
+    for (var i = 0; i < cardStringsToProcess.Count; i++)
+    {
+      var currentCardString = cardStringsToProcess[i];
+      var currentCardStringIndex = Array.IndexOf(cards, currentCardString);
+      var currentCard = Card.Parse(currentCardString);
+      var numOfMatchingNumbersForCurrentCard = currentCard.MatchingNumbers.Count;
+      var cardIndexesToCopy = Enumerable.Range(
+        currentCardStringIndex + 1,
+        Math.Min(
+          numOfMatchingNumbersForCurrentCard,
+          cards.Length - currentCardStringIndex - 1
+        )
+      );
+
+      foreach (var index in cardIndexesToCopy)
+      {
+        cardStringsToProcess.Add(cards[index]);
+      }
+    }
+
+    return cardStringsToProcess.Count;
+  }
 }
 
+/// <summary>
+/// Represents a card.
+/// </summary>
+/// <param name="id">The identifier.</param>
+/// <param name="winningNumbers">The winning numbers.</param>
+/// <param name="numbers">The numbers.</param>
+/// <returns>An instance of <see cref="Card"/>.</returns>
 public class Card(
   int id,
   List<int> winningNumbers,
   List<int> numbers
 )
 {
+  /// <summary>
+  /// Gets the identifier.
+  /// </summary>
   public int Id { get; init; } = id;
+
+  /// <summary>
+  /// Gets the winning numbers.
+  /// </summary>
   public List<int> WinningNumbers { get; init; } = winningNumbers;
+
+  /// <summary>
+  /// Gets the numbers.
+  /// </summary>
   public List<int> Numbers { get; init; } = numbers;
 
-  public int GetCardValue()
-  {
-    var commonNumbers = WinningNumbers.Intersect(Numbers).ToList();
+  /// <summary>
+  /// Gets the matching numbers.
+  /// </summary>
+  public List<int> MatchingNumbers => Numbers.Intersect(WinningNumbers).ToList();
 
-    return commonNumbers.Count is 1
-      ? 1
-      : (int)Math.Pow(2, commonNumbers.Count - 1);
-  }
+  /// <summary>
+  /// Gets the value of the card.
+  /// </summary>
+  /// <returns>The value of the card.</returns>
+  public int GetCardValue() => MatchingNumbers.Count is 1
+    ? 1
+    : (int)Math.Pow(2, MatchingNumbers.Count - 1);
 
+  /// <summary>
+  /// Parses the specified input.
+  /// </summary>
+  /// <param name="input">The input.</param>
+  /// <returns>An instance of <see cref="Card"/>.</returns>
   public static Card Parse(string input)
   {
     var parts = input.Split(':');