advent-of-code/2020/d22/ex1/ex1.py

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2020-12-22 13:59:01 +01:00
#!/usr/bin/env python
import itertools
import sys
from collections import deque
from typing import Deque, List, Tuple
Deck = Deque[int]
def parse_decks(raw: List[str]) -> Tuple[Deck, Deck]:
deck_1 = deque(int(n) for n in itertools.takewhile(len, raw[1:]))
deck_2 = deque(
int(n) for n in itertools.islice(itertools.dropwhile(len, raw[1:]), 2, None)
)
return deck_1, deck_2
def play(deck_1: Deck, deck_2: Deck) -> Tuple[int, Deck]:
while len(deck_1) and len(deck_2):
left, right = deck_1.popleft(), deck_2.popleft()
if left > right:
deck_1.extend((left, right))
else:
deck_2.extend((right, left))
return (1, deck_1) if len(deck_1) else (2, deck_2)
def solve(raw: List[str]) -> int:
__, deck = play(*parse_decks(raw))
score = sum((i) * val for i, val in enumerate(reversed(deck), 1))
return score
def main() -> None:
input = [line.strip() for line in sys.stdin.readlines()]
print(solve(input))
if __name__ == "__main__":
main()