Day 8: Haunted Wasteland

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)
Code block support is not fully rolled out yet but likely will be in the middle of the event. Try to share solutions as both code blocks and using something such as https://topaz.github.io/paste/ , pastebin, or github (code blocks to future proof it for when 0.19 comes out and since code blocks currently function in some apps and some instances as well if they are running a 0.19 beta)

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

[-] morrowind@lemmy.ml 2 points 11 months ago

Crystal

!crystal_lang@lemmy.ml

part 1 was made way simpler after I made it a function for part 2
also I accidentally saw someone elses code, so I can't take full credit for figuring out how to do part 2

Input = File.read("input.txt").lines

Dirs = Input[0].chars.map {|c| c == 'L' ? 0 : 1}
Nodes = Hash(String, Tuple(String, String)).new
Input[2..].each {|line| Nodes[line[..2]] = {line[7..9], line[12..14]} }

# part 1
puts num_steps("AAA") {|a| a == "ZZZ"}

# part 2
currents = Nodes.keys.select {|node| node.ends_with?('A')}
steps = currents.map {|cur| num_steps(cur) {|a| a.ends_with? 'Z'}}
puts steps.reduce {|a, b| a.lcm(b)}

def num_steps(start)
	steps = 0
	Dirs.cycle do |dir|
		steps += 1
		start = Nodes[start][dir]
		break if yield start
	end
	steps.to_i64
end

this post was submitted on 08 Dec 2023

21 points (92.0% liked)

Advent Of Code

736 readers

1 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 2023

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. [2023 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

Ategon@programming.dev

Sigmatics@lemmy.ca

CameronDev@programming.dev