90 lines
2.2 KiB
Python
90 lines
2.2 KiB
Python
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#!/usr/bin/env python
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import enum
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import itertools
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import sys
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from typing import Iterable, Iterator, List, NamedTuple, Set
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class Point(NamedTuple):
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x: int
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y: int
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class Map(NamedTuple):
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east: Set[Point]
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south: Set[Point]
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dimensions: Point
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def solve(input: List[str]) -> int:
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def parse() -> Map:
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east, south = set(), set()
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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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continue
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if c == "v":
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south.add(Point(x, y))
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if c == ">":
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east.add(Point(x, y))
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return Map(east, south, Point(len(input), len(input[0])))
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def step(sea_cucumbers: Map) -> Map:
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def move_east(p: Point) -> Point:
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return Point(p.x, (p.y + 1) % sea_cucumbers.dimensions.y)
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def move_south(p: Point) -> Point:
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return Point((p.x + 1) % sea_cucumbers.dimensions.x, p.y)
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east, south = set(), set()
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for old_p in sea_cucumbers.east:
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p = move_east(old_p)
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if p in sea_cucumbers.east or p in sea_cucumbers.south:
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east.add(old_p)
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continue
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east.add(p)
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for old_p in sea_cucumbers.south:
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p = move_south(old_p)
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if p in east or p in sea_cucumbers.south:
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south.add(old_p)
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continue
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south.add(p)
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return Map(east, south, sea_cucumbers.dimensions)
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def debug(map: Map) -> None:
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for x in range(map.dimensions.x):
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print(
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"".join(
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"v"
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if Point(x, y) in map.south
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else ">"
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if Point(x, y) in map.east
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else "."
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for y in range(map.dimensions.y)
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)
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)
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sea_cucumbers = parse()
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for i in itertools.count(1):
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if (new_map := step(sea_cucumbers)) == sea_cucumbers:
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return i
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print(i)
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sea_cucumbers = new_map
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assert False # Sanity check
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def main() -> None:
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input = [line.rstrip("\n") for line in sys.stdin.readlines()]
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print(solve(input))
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if __name__ == "__main__":
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main()
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