AdventOfCode23/Day12/Arrangement.cs

namespace Day12;

public class Arrangement
{
    private readonly IList<byte> _items;
    
    public Arrangement(string arrangement)
    {
        _items = arrangement.Select(c =>
        {
            switch (c)
            {
                case '.':
                    return (byte) 0;
                case '#':
                    return (byte) 1;
                default:
                    return (byte) 255;
            }
        }).ToList();
    }

    public Checksum CalculateChecksum()
    {
        var values = new List<int>();
        var c = 0;
        foreach (var i in _items)
        {
            if (i == 1)
            {
                c++;
            }
            else if (c > 0)
            {
                values.Add(c);
                c = 0;
            }
        }

        return new Checksum(values.ToArray());
    }
}