mirror of
https://github.com/Crocmagnon/advent-of-code.git
synced 2024-11-05 14:23:58 +01:00
72 lines
2 KiB
Python
72 lines
2 KiB
Python
from dataclasses import dataclass
|
|
|
|
|
|
@dataclass
|
|
class Asteroid:
|
|
x: int
|
|
y: int
|
|
|
|
def __hash__(self):
|
|
return hash((self.x, self.y))
|
|
|
|
@staticmethod
|
|
def square_length(a: "Asteroid", b: "Asteroid"):
|
|
return (b.x - a.x) * (b.x - a.x) + (b.y - a.y) * (b.y - a.y)
|
|
|
|
@staticmethod
|
|
def cross_product(a: "Asteroid", b: "Asteroid", c: "Asteroid"):
|
|
return (c.y - a.y) * (b.x - a.x) - (c.x - a.x) * (b.y - a.y)
|
|
|
|
@staticmethod
|
|
def dot_product(a: "Asteroid", b: "Asteroid", c: "Asteroid"):
|
|
return (c.x - a.x) * (b.x - a.x) + (c.y - a.y) * (b.y - a.y)
|
|
|
|
@staticmethod
|
|
def is_between(a: "Asteroid", b: "Asteroid", c: "Asteroid"):
|
|
"""Check if c is between a and b."""
|
|
cross_product = Asteroid.cross_product(a, b, c)
|
|
|
|
# compare versus epsilon for floating point values, or != 0 if using integers
|
|
if abs(cross_product) != 0:
|
|
return False
|
|
|
|
dot_product = Asteroid.dot_product(a, b, c)
|
|
if dot_product < 0:
|
|
return False
|
|
|
|
squared_length_ba = Asteroid.square_length(a, b)
|
|
if dot_product > squared_length_ba:
|
|
return False
|
|
|
|
return True
|
|
|
|
def can_see(self, other: "Asteroid", asteroids: set["Asteroid"]) -> bool:
|
|
for asteroid in asteroids:
|
|
if asteroid in [self, other]:
|
|
continue
|
|
if Asteroid.is_between(self, other, asteroid):
|
|
return False
|
|
return True
|
|
|
|
|
|
def main():
|
|
asteroids = set()
|
|
with open("inputs/day10") as f:
|
|
for y, line in enumerate(f):
|
|
for x, pixel in enumerate(line):
|
|
if pixel == "#":
|
|
asteroids.add(Asteroid(x, y))
|
|
|
|
max_visible = 0
|
|
for source in asteroids:
|
|
visible = 0
|
|
for destination in asteroids:
|
|
if destination != source and source.can_see(destination, asteroids):
|
|
visible += 1
|
|
if visible > max_visible:
|
|
max_visible = visible
|
|
print(max_visible)
|
|
|
|
|
|
if __name__ == "__main__":
|
|
main()
|