advent2023day4p2.py

gistfile1.txt

#!/usr/bin/env python

from functools import cache

real = True

with open("real_1.txt" if real else "test_1.txt") as infile:
    data = infile.read().strip()


def matches_in(card):
    card_num, numbers = card.strip().split(": ")
    they, me = numbers.split(" | ")
    they_have = {int(_) for _ in they.split()}
    i_have = {int(_) for _ in me.split()}
    matches = len(they_have & i_have)

    return int(card_num.split()[1]), matches


cards = {}
for card in data.splitlines():
    card_num, matches = matches_in(card)
    cards[card_num] = matches

@cache
def score(card_num):
    matches = cards[card_num]
    if not matches:
        return 1
    return 1 + sum(score(card_num + n + 1) for n in range(matches))


print(sum(score(card_num) for card_num in cards.keys()))