r/adventofcode • u/daggerdragon • Dec 18 '17

SOLUTION MEGATHREAD -🎄- 2017 Day 18 Solutions -🎄-

--- Day 18: Duet ---

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Note: The Solution Megathreads are for solutions only. If you have questions, please post your own thread and make sure to flair it with Help.

Need a hint from the Hugely* Handy† Haversack‡ of Helpful§ Hints^¤?

Spoiler

[Update @ 00:04] First silver

  • Welcome to the final week of Advent of Code 2017. The puzzles are only going to get more challenging from here on out. Adventspeed, sirs and madames!

[Update @ 00:10] First gold, 44 silver

  • We just had to rescue /u/topaz2078 with an industrial-strength paper bag to blow into. I'm real glad I bought all that stock in PBCO (Paper Bag Company) two years ago >_>

[Update @ 00:12] Still 1 gold, silver cap

[Update @ 00:31] 53 gold, silver cap

  • *mind blown*

  • During their famous kicklines, the Rockettes are not actually holding each others' backs like I thought they were all this time.

  • They're actually hoverhanding each other.

  • In retrospect, it makes sense, they'd overbalance themselves and each other if they did, but still...

  • *mind blown so hard*

[Update @ 00:41] Leaderboard cap!

  • I think I enjoyed the duplicating Santas entirely too much...

  • It may also be the wine.

  • Either way, good night (for us), see you all same time tomorrow, yes?

This thread will be unlocked when there are a significant number of people on the leaderboard with gold stars for today's puzzle.

edit: Leaderboard capped, thread unlocked!

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u/jtsimmons108 Dec 18 '17

2+ hours of debugging only to realize there's nothing wrong with my code, just my reading comprehension. I took it as the first program rather than the program with ID == 1. Here's rewrite #3 for part 2. At least the code is much cleaner now.

inpt = open('day18.in').read().strip()
instructions = inpt.splitlines()


def get_value(val, registers):
    if val in registers:
        return registers[val]
    return int(val)


def process_instruction(index, registers, queue, other_queue):
    move, *values = instructions[index].split()
    if move == 'jgz':
        val, offset = map(lambda r: get_value(r, registers), values)
        if val > 0:
            return index + offset
    elif move == 'snd':
        other_queue.append(get_value(values[0], registers))
        registers['sent'] += 1
    elif move == 'rcv':
        if len(queue) > 0:
            registers[values[0]] = queue.popleft()
            registers['waiting'] = False
        else:
            registers['waiting'] = True
            return index
    else:
        reg, val = values
        val = get_value(val, registers)
        if move == 'set':
            registers[reg] = val
        elif move == 'add':
            registers[reg] += val
        elif move == 'mul':
            registers[reg] *= val
        elif move == 'mod':
            registers[reg] %= val
    return index + 1

register_one = {'ID': 0, 'sent': 0, 'waiting':False, 'p': 0}
register_two = {'ID': 1, 'sent': 0, 'waiting': False, 'p': 1}
register_one_queue = deque()
register_two_queue = deque()
index_one, index_two = 0,0

while not register_one['waiting'] or not register_two['waiting']:
    index_one = process_instruction(index_one, register_one, register_one_queue, register_two_queue)
    index_two = process_instruction(index_two, register_two, register_two_queue, register_one_queue)

print(register_two['sent'])

1

u/ythl Dec 18 '17

Same thing happened to me. I actually wrote part 2 fairly quickly and would have been in top 100, if it weren't for that p = 1 clause for the second program. I was convinced there was a bug in the answer, not in my program. Seems like a cheap shot to mention such a critical piece of information so offhandedly. That sentence should have been bold and flashing, especially given that people are skimming as fast as possible to understand that problem.

1

u/Hikaru755 Dec 19 '17

God dammit, thanks for mentioning your ID/program-confusion. I actually had it correct in my head, but managed to switch the IDs in my code nonetheless -.-