public override Output Part2()
{
var input = Input.Lines();
var grid = new SparsePlaneGrid2D <int>(input[0].Length, input.Length);
for (int y = 0; y < input.Length; y++)
{
for (int x = 0; x < input[y].Length; x++)
{
grid[x, y] = Int32.Parse(input[y][x].ToString()) + 1;
}
}
List <Coordinate2D> flashes = new();
long answer = 0;
var i = 0;
while (true)
{
flashes.Clear();
for (int y = 0; y < grid.J.Length; y++)
{
for (int x = 0; x < grid.I.Length; x++)
{
Increase(x, y);
}
}
if (flashes.Count == grid.Count())
{
return(i + 1);
}
i++;
}
void Increase(long x, long y)
{
if (flashes.Contains(new(x, y)))
{
return;
}
grid[x, y]++;
if (grid[x, y] == 11)
{
answer++;
grid[x, y] = 1;
if (!flashes.Contains(new(x, y)))
{
flashes.Add(new(x, y));
var ns = grid.Neighbors(new(x, y));
foreach (var n in ns)
{
Increase(n.X, n.Y);
}
}
}
}
}
public override Output Part2()
{
var input = Input.Paragraphs();
var algorithm = input[0].Replace("\n", "");
var imageData = input[1].Lines();
var grid = new SparsePlaneGrid2D <bool>();
for (int y = 0; y < imageData.Length; y++)
{
for (int x = 0; x < imageData[y].Length; x++)
{
grid[x, y] = imageData[y][x] == '#';
}
}
var x0 = 0;
var xN = imageData[0].Length;
var y0 = 0;
var yN = imageData.Length;
for (int t = 0; t < 50; t++)
{
x0--;
xN++;
y0--;
yN++;
var newDefault = (grid.DefaultValue ? algorithm.Last() : algorithm.First()) == '#';
var newGrid = new SparsePlaneGrid2D <bool>(newDefault);
for (var y = y0; y <= yN; y++)
{
for (var x = x0; x <= xN; x++)
{
var rule = 0;
rule = rule * 2 + (grid[x - 1, y - 1] ? 1 : 0);
rule = rule * 2 + (grid[x, y - 1] ? 1 : 0);
rule = rule * 2 + (grid[x + 1, y - 1] ? 1 : 0);
rule = rule * 2 + (grid[x - 1, y] ? 1 : 0);
rule = rule * 2 + (grid[x, y] ? 1 : 0);
rule = rule * 2 + (grid[x + 1, y] ? 1 : 0);
rule = rule * 2 + (grid[x - 1, y + 1] ? 1 : 0);
rule = rule * 2 + (grid[x, y + 1] ? 1 : 0);
rule = rule * 2 + (grid[x + 1, y + 1] ? 1 : 0);
newGrid[x, y] = algorithm[rule] == '#';
}
}
grid = newGrid;
}
return(grid.Count(x => x.Value));
}