66 lines
1.5 KiB
Python
66 lines
1.5 KiB
Python
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#!/usr/bin/env python
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import itertools
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import sys
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from typing import Iterator, Set, Tuple
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Point = Tuple[int, int, int]
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Grid = Set[Point]
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def update(grid: Grid) -> Grid:
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def neightbours(p: Point) -> Iterator[Point]:
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for dx, dy, dz in itertools.product(range(-1, 2), repeat=3):
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if dx == 0 and dy == 0 and dz == 0:
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continue
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yield p[0] + dx, p[1] + dy, p[2] + dz
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def count_neighbours(p: Point) -> int:
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return sum(n in grid for n in neightbours(p))
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new_grid: Grid = set()
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seen: Set[Point] = set()
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for p in grid:
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for n in itertools.chain(neightbours(p), [p]):
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if n in seen:
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continue
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seen |= {n}
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active = n in grid
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num_neighbours = count_neighbours(n)
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if active and num_neighbours in [2, 3]:
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new_grid |= {n}
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elif active:
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continue
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elif num_neighbours == 3:
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new_grid |= {n}
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else:
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continue
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return new_grid
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def solve(grid: Grid) -> int:
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for __ in range(6):
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grid = update(grid)
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return len(grid)
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def main() -> None:
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input = [line.strip() for line in sys.stdin.readlines()]
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print(
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solve(
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{
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(i, j, 0)
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for i, line in enumerate(input)
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for j, x in enumerate(line)
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if x == "#"
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}
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)
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)
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if __name__ == "__main__":
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main()
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