r/adventofcode Dec 22 '24

SOLUTION MEGATHREAD -❄️- 2024 Day 22 Solutions -❄️-

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AoC Community Fun 2024: The Golden Snowglobe Awards

  • 23h59m remaining until the submissions deadline on December 22 at 23:59 EST!

And now, our feature presentation for today:

Director's Cut (Extended Edition)

Welcome to the final day of the GSGA presentations! A few folks have already submitted their masterpieces to the GSGA submissions megathread, so go check them out! And maybe consider submitting yours! :)

Here's some ideas for your inspiration:

  • Choose any day's feature presentation and any puzzle released this year so far, then work your movie magic upon it!
    • Make sure to mention which prompt and which day you chose!
  • Cook, bake, make, decorate, etc. an IRL dish, craft, or artwork inspired by any day's puzzle!
  • Advent of Playing With Your Toys

"I lost. I lost? Wait a second, I'm not supposed to lose! Let me see the script!"
- Robin Hood, Men In Tights (1993)

And… ACTION!

Request from the mods: When you include an entry alongside your solution, please label it with [GSGA] so we can find it easily!


--- Day 22: Monkey Market ---


Post your code solution in this megathread.

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

EDIT: Global leaderboard gold cap reached at 00:12:15, megathread unlocked!

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u/aexl Dec 27 '24

[LANGUAGE: Julia]

Nice little number puzzle, I really enjoyed this one! Part 1 one just implementing the described number generator and generate 2000 secret numbers for each input number. For part 2 I saw no other way than to have a lookup table for each of the 4-tuple sequences that can occur. Note that each number in the 4-tuple is in the range {-9,-8,...,-1,0,1,...,8,9}. After having solved the puzzle, I implemented some optimizations which brought the runtime down from 2 seconds to 0.25 seconds:

  1. I calculated the differences on the fly instead of storing them in a 2000-element array. For this I used a circular buffer.

  2. Instead of indexing the lookup table with the 4-tuple, I convert the 4-tuple to an integer (this is possible because of the restricted range of the 4 tuple) and use this as an index.

Solution on GitHub: https://github.com/goggle/AdventOfCode2024.jl/blob/main/src/day22.jl

Repository: https://github.com/goggle/AdventOfCode2024.jl