advent-of-code/2017/d20/ex2/ex2.py

57 lines
1.4 KiB
Python
Executable file

#!/usr/bin/env python
import collections
import sys
from typing import NamedTuple
class Point(NamedTuple):
x: int
y: int
z: int
class Particle(NamedTuple):
pos: Point
vel: Point
acc: Point
@classmethod
def from_str(cls, input: str) -> "Particle":
p, v, a = input.split(", ")
return cls(
Point(*map(int, p[3:-1].split(","))),
Point(*map(int, v[3:-1].split(","))),
Point(*map(int, a[3:-1].split(","))),
)
def tick(self) -> "Particle":
pos, vel, acc = self
vel = Point(*((v + a) for v, a in zip(vel, acc)))
pos = Point(*((p + v) for p, v in zip(pos, vel)))
return Particle(pos, vel, acc)
def solve(input: str) -> int:
def parse(input: str) -> list[Particle]:
return [Particle.from_str(line) for line in input.splitlines()]
def tick(particles: list[Particle]) -> list[Particle]:
particles = [p.tick() for p in particles]
positions = collections.Counter(p.pos for p in particles)
return [p for p in particles if positions[p.pos] == 1]
particles = parse(input)
# Guesstimate that 1000 iterations is enough to process all colisions
for _ in range(1000):
particles = tick(particles)
return len(particles)
def main() -> None:
input = sys.stdin.read()
print(solve(input))
if __name__ == "__main__":
main()