96 lines
2.2 KiB
Python
Executable file
96 lines
2.2 KiB
Python
Executable file
#!/usr/bin/env python
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import collections
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import dataclasses
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import enum
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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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class Direction(enum.Enum):
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UP = Point(-1, 0)
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DOWN = Point(1, 0)
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LEFT = Point(0, -1)
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RIGHT = Point(0, 1)
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def left(self) -> "Direction":
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x, y = self.value
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return Direction(Point(-y, x))
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def right(self) -> "Direction":
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x, y = self.value
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return Direction(Point(y, -x))
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def flip(self) -> "Direction":
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x, y = self.value
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return Direction(Point(-x, -y))
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def apply(self, p: Point) -> Point:
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dx, dy = self.value
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return Point(p.x + dx, p.y + dy)
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class State(enum.StrEnum):
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CLEAN = "."
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WEAKENED = "W"
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FLAGGED = "F"
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INFECTED = "#"
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@dataclasses.dataclass
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class Carrier:
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pos: Point
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dir: Direction
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def burst(self, infected: dict[Point, State]) -> bool:
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infect = False
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match infected[self.pos]:
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case State.CLEAN:
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self.dir = self.dir.left()
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infected[self.pos] = State.WEAKENED
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case State.WEAKENED:
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infected[self.pos] = State.INFECTED
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infect = True
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case State.FLAGGED:
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self.dir = self.dir.flip()
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infected[self.pos] = State.CLEAN
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case State.INFECTED:
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self.dir = self.dir.right()
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infected[self.pos] = State.FLAGGED
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self.pos = self.dir.apply(self.pos)
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return infect
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def solve(input: str) -> int:
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def parse(input: 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.splitlines())
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for y, c in enumerate(line)
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if c == "#"
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}
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infected: dict[Point, State] = collections.defaultdict(lambda: State.CLEAN)
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for p in parse(input):
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infected[p] = State.INFECTED
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middle = len(input.splitlines()) // 2
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carrier = Carrier(Point(middle, middle), Direction.UP)
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total = 0
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for _ in range(10000000):
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total += carrier.burst(infected)
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return total
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def main() -> None:
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input = sys.stdin.read()
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print(solve(input))
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if __name__ == "__main__":
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main()
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