namespace _2024;

public class Day02 : ISolution
{
    public void Run()
    {
        var input = File.ReadAllText("input/02")
            .Split('\n')
            .Select(line => line.Split(' ')
                .Select(int.Parse)
                .ToList())
            .ToList();

        Console.WriteLine(PartOne(input));
    }
    
    private static int PartOne(List<List<int>> list) {
        return list.Select(line => Enumerable.Range(1, Math.Max(0, line.Count - 1))
                .Select(i => line[i] - line[i - 1])
                .ToList())
            .Where(diffs => diffs.All(d => d > 0) || diffs.All(d => d < 0))
            .Count(diffs => !diffs.Any(d => Math.Abs(d) is < 1 or > 3));
    }
}