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
2 points
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 ^^’
2 points
*
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
2 points
2 points
*
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.
