Advent Of Code

920 readers

4 users here now

An unofficial home for the advent of code community on programming.dev!

Advent of Code is an annual Advent calendar of small programming puzzles for a variety of skill sets and skill levels that can be solved in any programming language you like.

AoC 2024

Solution Threads

M	T	W	T	F	S	S
						1
2	3	4	5	6	7	8
9	10	11	12	13	14	15
16	17	18	19	20	21	22
23	24	25

Rules/Guidelines

Follow the programming.dev instance rules
Keep all content related to advent of code in some way
If what youre posting relates to a day, put in brackets the year and then day number in front of the post title (e.g. [2024 Day 10])
When an event is running, keep solutions in the solution megathread to avoid the community getting spammed with posts

Relevant Communities

Relevant Links

Advent of Code Homepage

Credits

Icon base by Lorc under CC BY 3.0 with modifications to add a gradient

console.log('Hello World')

founded 1 year ago

MODERATORS

[email protected]

💂 - 2024 DAY 6 SOLUTIONS - 💂 (programming.dev)

submitted 1 month ago by [email protected] to c/[email protected]

40 comments fedilink hide all child comments

Day 6: Guard Gallivant

Megathread guidelines

Keep top level comments as only solutions, if you want to say something other than a solution put it in a new post. (replies to comments can be whatever)
You can send code in code blocks by using three backticks, the code, and then three backticks or use something such as https://topaz.github.io/paste/ if you prefer sending it through a URL

FAQ

What is this?: Here is a post with a large amount of details: https://programming.dev/post/6637268
Where do I participate?: https://adventofcode.com/
Is there a leaderboard for the community?: We have a programming.dev leaderboard with the info on how to join in this post: https://programming.dev/post/6631465

you are viewing a single comment's thread
view the rest of the comments

[–] Leavingoldhabits 3 points 4 weeks ago* (last edited 4 weeks ago) (9 children)

Rust

This one was the first real think for this year, but I ended up brute forcing it, placing a ‘#’ in every position and checking. part 2 runs in about ~~380ms~~ 78ms (after reducing the amount ‘#’-placements to only where the guard walks) on my 2011 core i-7, so I’m happy, even though it feels like I could have been smarter.

Part 1 Part 2

[–] [email protected] 2 points 4 weeks ago* (last edited 4 weeks ago) (8 children)

I am doing the same principle brute force but it takes ~7 seconds oO

Is using a HashSet<(Pos, Dir)> for the loop detection so expensive? My CPU shouldn't be THAT bad..

Part one around 7ms.

Also curious that i have not seen someone mention a more efficient approach, there gotta be one?

[–] Leavingoldhabits 2 points 4 weeks ago* (last edited 4 weeks ago) (1 children)

I’d like to see your solution in total. I’m not too familiar with the nuts and bolts, but hash set is quite a bit more expensive than a simple vector, there’s a bunch of overhead incurred when executing the hashing and placing of the data, and when repeating a few thousand times it sure adds up. My part one hovers around 600 microseconds.

[–] [email protected] 2 points 4 weeks ago

I’d like to see your solution in total.

I set it up a bit like a game, https://pastebin.com/FGA6E7fA

My part one hovers around 600 microseconds.

Ohhh, that says my part 1 is slow already, i was sure my approach for 2 was the problem. Good to know!

load more comments (6 replies)