6
votes
Day 24: Arithmetic Logic Unit
Today's problem description: https://adventofcode.com/2021/day/24
Please post your solutions in your own top-level comment. Here's a template you can copy-paste into your comment to format it nicely, with the code collapsed by default inside an expandable section with syntax highlighting (you can replace python with any of the "short names" listed in this page of supported languages):
<details>
<summary>Part 1</summary>
```python
Your code here.
```
</details>
Anyone have a hint for part 1? Seems like building the ALU is the easy part, and the real challenge is figuring out what the validator program does since a brute-force approach (trying every 14-digit number in descending order) doesn't seem to return in any reasonable amount of time.
I tried looking at the validator's output for 20 consecutive inputs, but it doesn't seem to give any clear indication of how to hone in on the maximum (or any) valid input in a non-brute-force way.
Edit: I looked at some reddit threads on this day's puzzle. I have no idea what anyone is talking about. Prooooobably gonna skip this one 😅