day 09
smoke basin
for part one, simply count the number of cells in which all neighbors are strictly greater.
for part two, floodfill until you have previously visited or until you find a height 9
python
def floodfill(grid, r, c):
if grid[r][c] is None or grid[r][c] == 9:
return 0
s, grid[r][c] = 1, None
for nr, nc in neighbors(grid, r, c):
s += floodfill(grid, nr, nc)
return s