AdventOfCode23/Day4/Program.cs

using Day4;

if (args.Length < 1)
{
    Console.WriteLine("Requires 1 args: inputFileName");
    return -1;
}

var inputFile = args[0];
var parser = new ScratchParser();
var cards = parser.Parse(inputFile).ToList();

var sum = 0;
foreach (var card in cards)
{
    var score = card.GetScore();
    sum += score;
}

Console.WriteLine();
Console.WriteLine($"Total Score: {sum}");

var copies = new Dictionary<int, int>();
sum = 0;
foreach (var item in cards.Select((c, i) => (card: c, index: i)))
{
    var matches = item.card.GetMatches();
    var copyCount = copies.GetValueOrDefault(item.index, 0) + 1;
    Console.WriteLine($"{item.index}: {matches} matches - {copyCount} copies");
    for (var i = 1; i <= matches; i++)
    {
        if (!copies.ContainsKey(item.index + i))
        {
            copies[item.index + i] = 0;
        }

        copies[item.index + i] += copyCount;
    }
    sum += copyCount;
}

Console.WriteLine();
Console.WriteLine($"Card Count: {sum}");

return 0;