def part_two(grid: Grid) -> int:
low_points = [p for p, v in grid.search(mindepth)]
sizes = []
for lp in low_points:
matches = list(grid.collect_recursive([lp], notnine))
sizes.append(len(matches))
top3 = sorted(sizes, reverse=True)[:3]
return math.prod(top3)
def part_one(grid: Grid) -> int:
return sum(val + 1 for _, val in grid.search(mindepth))