Advent of Code 2023 Day 4

Author

Nathan Moore

— Day 4: Scratchcards —

There are lots of scratchcards, with your numbers, and winning numbers. The point value of each card doubles with the number of winning numbers you have i.e. 1, 2, 4, 8, etc.

Take a seat in the large pile of colorful cards. How many points are they worth in total?

with open('data-2023-04.txt', 'r') as f:
    inp = f.read().splitlines()

This seems simple enough. Probably?

# here's another python cell for good luck

cards = {x.split(':')[0]: x.split(':')[1] for x in inp}

summer = 0

for k,v in cards.items():
    pt = 0
    win_num = v.split('|')[0].split()
    my_num = v.split('|')[1].split()
    for m in my_num: 
        if m in win_num: 
            if pt == 0:
                pt = 1
            else: 
                pt *= 2
    # add the results
    summer += pt
    
summer

Part one: 28538

— Part Two —

Actually you win more copies of scratchcards somehow?

Process all of the original and copied scratchcards until no more scratchcards are won. Including the original set of scratchcards, how many total scratchcards do you end up with?

import re

cards = {x.split(':')[0]: x.split(':')[1] for x in inp}
crd_cnt = {}

for k,v in cards.items():
    crd_cnt[k] = 1

for k,v in cards.items():
    # initialise for each loop
    pt = 0
    n = int(re.findall(r'\d+', k)[0])
    # split the cards into winning numbers and my numbers
    win_num = v.split('|')[0].split()
    my_num = v.split('|')[1].split()
    # loop to find how many winning numbers I have
    for m in my_num: 
        if m in win_num: 
            pt += 1
    # find how many cards we have at the moment
    j = crd_cnt[k]
    # pt is the number of following cards
    for i in range(n+1, n+pt+1):
        cn = 'Card' + str(i).rjust(4)
        crd_cnt[cn] += j
        
summer = 0

for k,v in crd_cnt.items():
    summer += v
    
summer

Part two: 9,425,061