advent-of-code/2023/d11/ex1/ex1.py

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2023-12-11 08:05:54 +01:00
#!/usr/bin/env python
import dataclasses
import sys
from typing import NamedTuple
class Point(NamedTuple):
x: int
y: int
@dataclasses.dataclass
class Expansion:
lines: set[int]
rows: set[int]
def solve(input: list[str]) -> int:
def parse(input: list[str]) -> tuple[list[Point], Expansion]:
res: list[Point] = []
expansion = Expansion(set(range(len(input))), set(range(len(input[0]))))
for x, line in enumerate(input):
for y, c in enumerate(line):
if c != "#":
continue
res.append(Point(x, y))
expansion.lines.discard(x)
expansion.rows.discard(y)
return res, expansion
def do_expansion(galaxies: list[Point], expansion: Expansion) -> list[Point]:
new_lines = [0] * len(input)
new_rows = [0] * len(input[0])
for i in range(len(new_lines)):
new_lines[i] = new_lines[i - 1] + (i in expansion.lines) + 1
for i in range(len(new_rows)):
new_rows[i] = new_rows[i - 1] + (i in expansion.rows) + 1
return [Point(new_lines[p.x], new_rows[p.y]) for p in galaxies]
def dist(a: Point, b: Point) -> int:
return abs(a.x - b.x) + abs(a.y - b.y)
galaxies, expansion = parse(input)
galaxies = do_expansion(galaxies, expansion)
return sum(
dist(galaxies[i], galaxies[j])
for i in range(len(galaxies))
for j in range(i + 1, len(galaxies))
)
def main() -> None:
input = sys.stdin.read().splitlines()
print(solve(input))
if __name__ == "__main__":
main()