Advent of code 2023 day 11 fastest

def day11(s, *, part2=False):
  expand = 1_000_000 if part2 else 2
  grid = np.array([list(line) for line in s.splitlines()])
  coords = np.argwhere(grid == '#').T

  def process(values):
    total = last_value = num = 0
    for value, group in itertools.groupby(values):
      spacing = 1 + (value - last_value - 1) * expand
      total += num * (len(values) - num) * spacing
      num += len(list(group))
      last_value = value
    return total

  return process(coords[0]) + process(sorted(coords[1]))