Advent of code 2023 day 13

def day13(s, *, part2=False):
  num_diff = 1 if part2 else 0
  total = 0

  for section in s.split('\n\n'):
    grid = np.array([list(line) for line in section.splitlines()])

    reflections = []
    for axis in range(2):
      for i in range(1, len(grid)):
        h = min(i, len(grid) - i)  # Shortest height.
        if np.sum(grid[i - h : i] != grid[i : i + h][::-1]) == num_diff:
          reflections.append((axis, i))
      grid = grid.T

    ((axis, i),) = reflections
    total += i * [100, 1][axis]

  return total