Advent of code 2022 day 24

@numba.njit
def min_time_at_dst(grid, time, start_yx, dst_yx):
  shape = grid.shape
  active = {start_yx}
  max_time = time + shape[0] + shape[1] + 150  # 113 is min for my puzzle input.

  while active:
    new_active = set()
    time += 1
    for y, x in active:
      for dy, dx in ((1, 0), (0, 1), (0, 0), (-1, 0), (0, -1)):
        yx2 = y2, x2 = y + dy, x + dx
        if yx2 == dst_yx:
          return time
        if (0 <= y2 < shape[0] and 0 <= x2 < shape[1] and
            grid[y2, (x2 - time) % shape[1]] != '>' and
            grid[y2, (x2 + time) % shape[1]] != '<' and
            grid[(y2 - time) % shape[0], x2] != 'v' and
            grid[(y2 + time) % shape[0], x2] != '^') or yx2 == start_yx:
          remaining_dist = abs(y2 - dst_yx[0]) + abs(x2 - dst_yx[1])
          if time + remaining_dist <= max_time:
            new_active.add(yx2)
    active = new_active

  raise AssertionError('No path found; try increasing max_time.')


def day24(s, *, part2=False):
  grid = np.array([list(line) for line in s.splitlines()])
  grid = grid[1:-1, 1:-1]  # (5, 5) or (35, 100); lcm=700 is large.
  start, final = (-1, 0), (grid.shape[0], grid.shape[1] - 1)

  time1 = min_time_at_dst(grid, 0, start, final)
  if not part2:
    return time1
  time2 = min_time_at_dst(grid, time1, final, start)
  time3 = min_time_at_dst(grid, time2, start, final)
  return time3  # time1 = 225, time2 = 463, time3 = 711