Advent of code 2024 day 8

def day8(s, *, part2=False):
  grid = np.array([list(line) for line in s.splitlines()])
  antinodes = np.full(grid.shape, 0)
  for symbol in set(np.unique_values(grid)) - {'.'}:
    for pair in itertools.permutations(np.argwhere(grid == symbol), 2):
      for t in itertools.count(1) if part2 else [2]:
        y, x = (1 - t) * pair[0] + t * pair[1]
        if not (0 <= y < grid.shape[0] and 0 <= x < grid.shape[1]):
          break
        antinodes[y, x] = 1
  return antinodes.sum()