Advent Of Code

985 readers

62 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 12 SOLUTIONS -🌻 (programming.dev)

submitted 2 weeks ago by [email protected] to c/[email protected]

27 comments fedilink hide all child comments

Day 12: Garden Groups

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

[–] [email protected] 4 points 2 weeks ago* (last edited 1 week ago) (6 children)

Uiua

~~Takes about 3 seconds to solve both parts for live data, caused primarily by my terrible fill function in FieldCoords which repeatedly refills and dedups already discovered cells. I promised myself when I wrote it that I would revisit it, but I really can't be bothered right now. Sorry Kai.~~

LATE EDIT: Thanks to Quant for the inspiration to revisit this. With his code snippet and the realisation that I should normalise all fields to remove wasted space, runtime is now down to 55ms.

Data ← ⊜∘⊸≠@\n "AAAA\nBBCD\nBBCC\nEEEC"
N₄     ← [¯1_0 1_0 0_¯1 0_1]               # Four orthogonal neighbours.
Fences ← /+/+=0≡(⬚0⊡+N₄¤)⊙¤⊚.°⊚            # Fences for a field, by looking for edges.
Cs     ← [0 1 1 0 1 0 2 1 1 2 0 1 0 1 1 0] # Number of corners keyed by bitarray of 2x2 grid.
Sides  ← /+♭⬚0⧈(⊡:Cs°⋯♭)2_2°⊚              # Add border, look for corners in 2x2 windows.

# Use `classify` to find fields, then normalise to 0_0.
Fields ← ≡⍚(-¤⊸/↧)⊜□:⇡△.+1⍜♭⊛Data # Thanks to Quant!

/+×≡◇⊃⧻Fences Fields
/+×≡◇⊃⧻Sides Fields

[–] [email protected] 2 points 1 week ago (1 children)

I found multidimensional markers for partition to work really well for finding the fields: Areas ← ⊜□:⇡△.+1⍜♭⊛ It just groups the other array's contents according to adjacent markers, horizontally and vertically. Took me quite a bit to figure out what's actually happening in the example in the documentation ^^'

[–] [email protected] 2 points 1 week ago* (last edited 1 week ago) (1 children)

Ooh, interesting, I'll have to give that a try. Thanks!

(edit) Wow, that replaced my three lines of overly complex code without a hitch. classify is an operator I never really got the point of before. Beautiful.

Data ← ⊜∘⊸≠@\n "AAAA\nBBCD\nBBCC\nEEEC"
N₄     ← [¯1_0 1_0 0_¯1 0_1]               # Four orthogonal neighbours.
Fences ← /+≡(/+=0⬚0⊡+N₄¤)⊙¤⊚.°⊚            # Fences for a field, by looking for edges.
Cs     ← [0 1 1 0 1 0 2 1 1 2 0 1 0 1 1 0] # Number of corners keyed by bitarray of 2x2 grid.
Sides  ← /+/+⧈(⊡:Cs°⋯♭)2_2⌝↘¯1_¯1⌝↘1_1°⊚   # Add border, look for corners in 2x2 windows.

Fields ← ⊜□:⇡△.+1⍜♭⊛Data

/+×≡◇⊃⧻Fences Fields
/+×≡◇⊃⧻Sides Fields

[–] [email protected] 2 points 1 week ago (1 children)

Nice :D
How's the speed now?

[–] [email protected] 2 points 1 week ago* (last edited 1 week ago) (1 children)

1.8s now. 99% of that in Sides. I've just had an idea though... ~~maybe too late for today though!~~

edit: prepending ≡⍚(-¤⊸/↧) toFields spared me from manipulating hundreds of irrelevant 0's, so time is very good now at 55ms.

[–] [email protected] 2 points 1 week ago (1 children)

Damn that's a lot time saved. I love how unassuming the addition looks for how great an effect it has

[–] [email protected] 1 points 1 week ago

It was a real D'oh! moment when I visualised the data I was generating and saw all the zeros stretching across the page.

load more comments (4 replies)