advent-of-code/2021/d05/ex2/ex2.py

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2021-12-05 11:38:19 +01:00
#!/usr/bin/env python
import itertools
import sys
from collections import Counter
from typing import Iterable, List, NamedTuple, Tuple
class Point(NamedTuple):
x: int
y: int
Line = Tuple[Point, Point]
def solve(input: List[str]) -> int:
def parse_line(line: str) -> Line:
def parse_point(point: str) -> Point:
x, y = map(int, point.split(","))
return Point(x, y)
p1, p2 = map(parse_point, line.split(" -> "))
return (p1, p2)
def line_to_points(line: Line) -> Iterable[Point]:
def inclusive_range_any_order(a: int, b: int) -> Iterable[int]:
if a < b:
yield from range(a, b + 1)
else:
yield from range(a, b - 1, -1)
p1, p2 = line
xs = inclusive_range_any_order(p1.x, p2.x)
ys = inclusive_range_any_order(p1.y, p2.y)
if p1.x == p2.x:
xs = itertools.repeat(p1.x)
if p1.y == p2.y:
ys = itertools.repeat(p1.y)
yield from map(Point._make, zip(xs, ys))
lines = list(map(parse_line, input))
counts = Counter(itertools.chain.from_iterable(line_to_points(l) for l in lines))
return sum(counts[p] > 1 for p in counts)
def main() -> None:
input = [line.strip() for line in sys.stdin.readlines()]
print(solve(input))
if __name__ == "__main__":
main()