47 lines
1 KiB
Python
Executable file
47 lines
1 KiB
Python
Executable file
#!/usr/bin/env python
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import itertools
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import sys
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from typing import NamedTuple
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class Point(NamedTuple):
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x: int
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y: int
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def solve(input: list[str]) -> int:
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def parse(input: list[str]) -> set[Point]:
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return {
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Point(x, y)
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for x, line in enumerate(input)
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for y, c in enumerate(line)
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if c == "@"
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}
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def is_accessible(point: Point, rolls: set[Point]) -> bool:
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assert point in rolls # Sanity check
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return (
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sum(
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Point(point.x + dx, point.y + dy) in rolls
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for dx, dy in itertools.product(range(-1, 1 + 1), repeat=2)
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if dx != 0 or dy != 0
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)
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< 4
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)
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rolls = parse(input)
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removed = 0
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while accessible := {p for p in rolls if is_accessible(p, rolls)}:
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removed += len(accessible)
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rolls -= accessible
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return removed
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def main() -> None:
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input = sys.stdin.read().splitlines()
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print(solve(input))
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if __name__ == "__main__":
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main()
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