AoC11

class AoC11 : AdventOfCode
{
    Tilemap _octopuses;
    public AoC11() : base(11) { }
    
    public override void Run() {
        Run1();
        Run2();
    }
    public void Run1()
    {
        _octopuses = new Tilemap(inputFile);
        const int simulationStep = 100;
        var flashes = 0;
        for (int i = 0; i < simulationStep; i++)
            flashes += Step();

        WriteLine($"Cute flashes count:{flashes}");
    }
    public void Run2()
    {
        _octopuses = new Tilemap(inputFile);//Reset !
        var step = 1;
        while (Step() < _octopuses.Size)
            ++step;

        WriteLine($"All synchro flash at step:{step}");
    }

    readonly HashSet<int> _stepFlashes = new HashSet<int>();
    int Step()
    {
        _stepFlashes.Clear();
        for (int i = 0; i < _octopuses.Size; i++)
            Step(i);
        return _stepFlashes.Count;
    }
    void Step(int id)
    {
        if (_stepFlashes.Contains(id)) return;
        if (++_octopuses[id] >= 10) //Flash !
            Flash(id);
    }
    void Flash(int id)
    {
        if (!_stepFlashes.Add(id)) return;
        _octopuses[id] = 0;
        using var neighbors= _octopuses.Get8Neighbors(id);
        for (int i = 0; i < neighbors.Length; i++)
            Step(neighbors[i]);
    }
}