python(day22): Do day 22

This commit is contained in:
Sijmen 2020-12-24 16:16:11 +01:00
parent 81caf181b2
commit c1c649ed05
Signed by: vijfhoek
GPG Key ID: DAF7821E067D9C48
1 changed files with 124 additions and 0 deletions

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python/day22.py Normal file
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import fileinput
import itertools
from pprint import pprint
from collections import deque
from typing import List, Deque, Dict, Tuple, Optional, Set
from copy import deepcopy
Deck = Deque[int]
Decks = Dict[int, Deck]
FrozenDeck = Tuple[Tuple[int, ...], Tuple[int, ...]]
def parse() -> Decks:
decks: Decks = {}
deck: Optional[Deck] = None
player: Optional[int] = None
for line in fileinput.input():
line = line.strip()
if line.startswith("Player "):
if deck and player:
decks[player] = deck
deck = deque()
player = int(line[len("Player ") : -1])
elif line.isdigit():
assert deck is not None
deck.append(int(line))
if deck and player:
decks[player] = deck
return decks
def part1_round(decks: Decks):
p1 = decks[1].popleft()
p2 = decks[2].popleft()
assert p1 != p2
if p1 > p2:
decks[1].extend((p1, p2))
else:
decks[2].extend((p2, p1))
def part1(decks: Decks) -> None:
i = 0
while decks[1] and decks[2]:
part1_round(decks)
i += 1
winner = 1 if decks[1] else 2
score = sum(card * (i + 1) for i, card in enumerate(reversed(decks[winner])))
print("Part 1:", score, "(player", winner, "won)")
def freeze_decks(decks: Decks) -> FrozenDeck:
return (
tuple(decks[1]),
tuple(decks[2]),
)
def part2_round(decks: Decks, history: Set[FrozenDeck]):
frozen = freeze_decks(decks)
if frozen in history:
# Player 1 wins if the round happened before
return 1
if not decks[1]:
return 2
if not decks[2]:
return 1
history.add(frozen)
p1 = decks[1].popleft()
p2 = decks[2].popleft()
assert(p1 != p2)
if len(decks[1]) >= p1 and len(decks[2]) >= p2:
new_decks = {
1: deque(list(decks[1])[:p1]),
2: deque(list(decks[2])[:p2]),
}
winner = part2_game(new_decks)
elif p1 > p2:
winner = 1
else:
winner = 2
assert(winner == 1 or winner == 2)
if winner == 1:
decks[1].extend((p1, p2))
elif winner == 2:
decks[2].extend((p2, p1))
def part2_game(decks: Decks) -> Optional[int]:
i = 0
history: Set[FrozenDeck] = set()
winner: Optional[int] = None
while winner is None:
winner = part2_round(decks, history)
i += 1
return winner
def part2(decks: Decks) -> None:
winner = part2_game(decks)
assert(winner is not None)
score = sum(card * (i + 1) for i, card in enumerate(reversed(decks[winner])))
print("Part 2:", score, "(player", winner, "won)")
def main() -> None:
decks = parse()
part1(deepcopy(decks))
part2(decks)
if __name__ == "__main__":
main()