advent-of-code/2021/d25/ex1/ex1.py

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2021-12-25 16:55:18 +01:00
#!/usr/bin/env python
import enum
import itertools
import sys
from typing import Iterable, Iterator, List, NamedTuple, Set
class Point(NamedTuple):
x: int
y: int
class Map(NamedTuple):
east: Set[Point]
south: Set[Point]
dimensions: Point
def solve(input: List[str]) -> int:
def parse() -> Map:
east, south = set(), set()
for x, line in enumerate(input):
for y, c in enumerate(line):
if c == ".":
continue
if c == "v":
south.add(Point(x, y))
if c == ">":
east.add(Point(x, y))
return Map(east, south, Point(len(input), len(input[0])))
def step(sea_cucumbers: Map) -> Map:
def move_east(p: Point) -> Point:
return Point(p.x, (p.y + 1) % sea_cucumbers.dimensions.y)
def move_south(p: Point) -> Point:
return Point((p.x + 1) % sea_cucumbers.dimensions.x, p.y)
east, south = set(), set()
for old_p in sea_cucumbers.east:
p = move_east(old_p)
if p in sea_cucumbers.east or p in sea_cucumbers.south:
east.add(old_p)
continue
east.add(p)
for old_p in sea_cucumbers.south:
p = move_south(old_p)
if p in east or p in sea_cucumbers.south:
south.add(old_p)
continue
south.add(p)
return Map(east, south, sea_cucumbers.dimensions)
def debug(map: Map) -> None:
for x in range(map.dimensions.x):
print(
"".join(
"v"
if Point(x, y) in map.south
else ">"
if Point(x, y) in map.east
else "."
for y in range(map.dimensions.y)
)
)
sea_cucumbers = parse()
for i in itertools.count(1):
if (new_map := step(sea_cucumbers)) == sea_cucumbers:
return i
print(i)
sea_cucumbers = new_map
assert False # Sanity check
def main() -> None:
input = [line.rstrip("\n") for line in sys.stdin.readlines()]
print(solve(input))
if __name__ == "__main__":
main()