#define Day11
#if Day11
using AoC2021;

const int GRID_SIZE = 10;

var grid = File.ReadAllLines("day11/input")
    .SelectMany((l,row) =>
        l.Select((c, col) => new {pos = new Pos(row, col), v = int.Parse(c.ToString())}))
    .ToDictionary(x => x.pos, x => x.v);

long flashes = 0;
int flashesPerStep = 0;

int count = 0;
while (true) {
    flashesPerStep = 0;
    grid = grid.ToDictionary(x => x.Key, x => x.Value + 1);
    grid.Keys.ForEachAsList(p => grid = flash(p, grid));
    count++;
    if (flashesPerStep == 100) { Console.WriteLine(count); break; }

    if (count == 100) { Console.WriteLine(flashes); }
}

Dictionary<Pos, int> flash(Pos cur, Dictionary<Pos, int> grid) {
    if (grid[cur] < 10) {
        return grid;
    }

    flashes++;
    flashesPerStep++;
    grid[cur] = 0;

    var adjacent = GetAdjacent(cur);
    adjacent.Where(a => grid[a] != 0).ForEachAsList(a => grid[a] += 1);
    adjacent.Where(a=> grid[a] > 9).ForEachAsList(a => grid = flash(a, grid));
    return grid;
}

List<Pos> GetAdjacent(Pos p) => new List<Pos>() {
        new(p.row-1, p.col), new(p.row-1, p.col+1), new(p.row-1, p.col-1),
        new(p.row+1, p.col), new(p.row+1, p.col+1), new(p.row+1, p.col-1),
        new(p.row, p.col+1), new(p.row, p.col-1),
    }.Where(x => x.row >= 0 && x.row < GRID_SIZE && x.col >= 0 && x.col < GRID_SIZE).ToList();
record Pos(int row, int col);
#endif