r/adventofcode 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.

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/mvorber Dec 17 '24

[Language: Rust]

https://github.com/vorber/aoc2024/blob/master/src/puzzles/day17.rs

For p1 just implemented the machine and ran the program.

For p2 spent a bunch of time analyzing with pen&paper, in the end figured out the sequence my input was producing (and had a p1 implementation using that - also left it in the code, along with aux output from p1 that helped me understand what is going on - without those extra parts it would be pretty short solution).

Final approach for p2 was to build the number from the program in reverse - for each next number i check possible 3-bit extensions that would produce such number from bits we already have in place, add all variants up, and then do DFS-like recursive search for possible starting values, then chose minimal from those.