Advent of code 2024 day 20 jit symmetrized 5 ms

@numba.njit
def day20_jit(distance, ys, xs, ye, xe, part2, min_savings):
  d, y, x = 0, ys, xs
  distance[y, x] = d
  while (y, x) != (ye, xe):
    for y, x in ((y, x - 1), (y, x + 1), (y - 1, x), (y + 1, x)):
      if distance[y, x] == -1:
        break
    d += 1
    distance[y, x] = d

  radius = 20 if part2 else 2
  count = 0
  for (y, x), d in np.ndenumerate(distance):
    if d >= 0:
      for y2 in range(y, min(y + radius + 1, distance.shape[0] - 1)):
        radius_x = radius - abs(y2 - y)
        xt = x - radius_x if y2 > y else x + 1
        for x2 in range(max(xt, 0), min(x + radius_x + 1, distance.shape[1] - 1)):
          d2 = distance[y2, x2]
          if d2 >= 0:
            savings = abs(d2 - d) - abs(y2 - y) - abs(x2 - x)
            if savings >= min_savings:
              count += 1

  return count


def day20(s, *, part2=False, min_savings=100):
  grid = np.array([list(line) for line in s.splitlines()])
  ((ys, xs),) = np.argwhere(grid == 'S')
  ((ye, xe),) = np.argwhere(grid == 'E')
  distance = np.where(grid == '#', -2, -1)
  return day20_jit(distance, ys, xs, ye, xe, part2, min_savings)