advent-of-code/2021/d05/ex1/ex1.py

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2021-12-05 11:37:49 +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 is_of_interest(line: Line) -> bool:
p1, p2 = line
return p1.x == p2.x or p1.y == p2.y
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
if p1.x == p2.x:
for y in inclusive_range_any_order(p1.y, p2.y):
yield Point(p1.x, y)
return
if p1.y == p2.y:
for x in inclusive_range_any_order(p1.x, p2.x):
yield Point(x, p1.y)
return
assert False # Sanity check
lines = list(filter(is_of_interest, 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()