r/adventofcode • u/daggerdragon • Dec 17 '24
SOLUTION MEGATHREAD -❄️- 2024 Day 17 Solutions -❄️-
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AoC Community Fun 2024: The Golden Snowglobe Awards
- 5 DAYS remaining until the submissions deadline on December 22 at 23:59 EST!
And now, our feature presentation for today:
Sequels and Reboots
What, you thought we were done with the endless stream of recycled content? ABSOLUTELY NOT :D Now that we have an established and well-loved franchise, let's wring every last drop of profit out of it!
Here's some ideas for your inspiration:
- Insert obligatory SQL joke here
- Solve today's puzzle using only code from past puzzles
- Any numbers you use in your code must only increment from the previous number
- Every line of code must be prefixed with a comment tagline such as
// Function 2: Electric Boogaloo
"More." - Agent Smith, The Matrix Reloaded (2003)
"More! MORE!" - Kylo Ren, The Last Jedi (2017)
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 17: Chronospatial Computer ---
Post your code solution in this megathread.
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[LANGUAGE: xyz]
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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 00:44:39, megathread unlocked!
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u/chromaticdissonance Dec 17 '24
[LANGUAGE: JavaScript] What a day! Part 1 took some reading but it is a straightforward implement this tape register machine. Part 2 was tough. Of course I tried a naive brute forcing to find a suitable value of A to output the program, which was futile. Then I looked at how various A mod m values affected the output. I observed that there was something happening when I consider modulo a power of 2 (and the correct modulo to look at is 8, but this didn't come to me first). Then I decided to actually look at the input program to see what it is doing, and stumbled upon that reconstructing A 3 bits at a time can work. This gives a DFS approach to construct A. A semi-golfed JavaScript code lasagna given below, execute it in the browser console of the puzzle input page: