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#!/usr/bin/env python3
"""
Most of the code taken from this guys floodfill, I just adapted it for this problem
https://playandlearntocode.com/article/flood-fill-algorithm-in-python
"""
from functools import reduce
from itertools import product
from operator import mul
from libaoc import matrix, read_int_matrix
def is_basin(grid: matrix[int], row: int, col: int) -> bool:
return (
not ((row < 0 or row > len(grid) - 1) or (col < 0 or col > len(grid[0]) - 1))
and grid[row][col] != 9
)
def floodfill(grid: matrix[int], row: int, col: int) -> int:
if row < 0 or row > len(grid) - 1 or col < 0 or col > len(grid[0]) - 1 or grid[row][col] == 9:
return 0
q: list[tuple[int, int]] = []
grid[row][col] = 9
q.append((row, col))
size = 1
while len(q):
row, col = q.pop(0)
for x, y in ((-1, 0), (1, 0), (0, -1), (0, 1)):
c_row = row + x
c_col = col + y
if is_basin(grid, c_row, c_col):
grid[c_row][c_col] = 9
q.append((c_row, c_col))
size += 1
return size
def solve(grid: matrix[int]) -> int:
return reduce(
mul,
sorted(
map(
lambda t: floodfill(grid, t[0], t[1]),
filter(
lambda t: grid[t[0]][t[1]] != 9, product(range(len(grid)), range(len(grid[0]))),
),
)
)[-3:],
)
def main() -> None:
with open("input", "r", encoding="utf-8") as f:
print(solve(read_int_matrix(f)))
if __name__ == "__main__":
main()
|
