Learning Resources>Coding Challenges

Advent of Code 2021 - Day 9

#advent-of-code
bjorng

bjorng

Erlang Core Team

Advent of Code 2021 - Day 9

This topic is about Day 9 of the Advent of Code 2021 .

We have a private leaderboard (shared with users of Erlang Forums):

https://adventofcode.com/2021/leaderboard/private/view/370884

The entry code is:
370884-a6a71927

13 comments
#advent-of-code
7 2299 13

Most Liked

bjorng

bjorng

Erlang Core Team

I solved part two with a simple union-find algorithm. Since it finished in less than two seconds on my computer, I didn’t need to do any further optimizations.

https://github.com/bjorng/advent-of-code-2021/blob/49f0d8eff0110e6e5d823bf314236c6bf7dcc991/day09/lib/day09.ex

4
Post #2
deadbeef

deadbeef

For part two I did a sort-of breadth-first search (I think?). Feels a bit messy, but got the job done.
Also, felt my file’s a bit cruft-y with how many small functions I made, but was trying to make things reusable between parts.

https://github.com/ed-flanagan/advent-of-code-solutions-elixir/blob/main/lib/advent/y2021/d09.ex

1
Post #3
wasi0013

wasi0013

Here’s my solution: y2021/day_09.ex
For part 2 used bfs

1
Post #4

Where Next?

View thread on forum (has 13 responses!)
advent-of-code
Home Learning Resources>Coding Challenges
#advent-of-code
7 2306 13
Last post

Popular in Challenges Top

maennchen
Learning Resources>Coding Challenges

Advent of Code 2022 - Day 16
Ok, that was a rough one today. I haven’t found a way to improve the algorithm further. Part 1 runs in .5 seconds, Part 2 in ~ 5 minutes...
#advent-of-code#2022
3 1837 12
New
woolfred
Learning Resources>Coding Challenges

Advent of Code 2022 - Day 1
It is that time of the year again: Advent of Code 2022 :christmas_tree: Day 1 Leaderboard:
#advent-of-code#2022
44 3506 33
New
sasajuric
Learning Resources>Coding Challenges

Advent of Code - Day 12
Note: This topic is to talk about Day 12 of the Advent of Code. For general discussion about the Advent of Code 2018 and links to topics...
#2018#advent-of-code
7 1772 9
New
kwando
Learning Resources>Coding Challenges

Advent Of Code 2022 - Day 12
Phew, this one took a while to get right. My naive attempts was way to slow so I reached for Dijkstras shortest path algorithm.. and that...
#advent-of-code
13 1655 12
New
ehayun
Learning Resources>Coding Challenges

Array merge in elixir
I have 2 arrays: a1 can be any combination of value or nil like that a1 = [1,nil,3] and array 2 the same a2 = [4,2, nil] How do I com...
#elixir-ls
9 1499 2
New
Aetherus
Learning Resources>Coding Challenges

Advent of Code 2020 - Day 15
This topic is about Day 15 of the Advent of Code 2020 . Thanks to @egze, we have a private leaderboard: https://adventofcode.com/2020/l...
#2020#advent-of-code
25 2281 29
New
adamu
Learning Resources>Coding Challenges

Advent Of Code 2022 - Day 3
Probably not the most efficient implementation, because part 1 took >1 ms and part 2 >4ms, but the code was simple enough. def p...
#advent-of-code#2022
35 2062 36
New
rvnash
Learning Resources>Coding Challenges

Advent of Code 2024 - Day 24
Anyone have a solution to Part 2 today? Part 1 was straight forward, but I can’t figure out a programatic way to do part 2. I understand ...
#2024
25 739 21
New
Aetherus
Learning Resources>Coding Challenges

Advent of Code 2023 - Day 3
Don’t know why the regex ~r/[\W && [^\.]]/x does not work in Elixir. It works pretty well in Ruby. Anyway, here is my solution: ...
#advent-of-code#2023
41 2501 22
New
bjorng
Learning Resources>Coding Challenges

Advent of Code 2019 - Day 13
Note: This topic is to talk about Day 13 of the Advent of Code 2019. There is a private leaderboard for elixirforum members. You can joi...
#2019#advent-of-code
26 2195 24
New

Other popular topics Top

mcarvalho
Questions & Help>Questions

System.get_env vs. Application.get_env
What is the difference between System.get_env and Application.get_env? For example, what are best practices to use one versus another.
#environment
13 17200 6
New
lessless
Questions & Help>Questions

How are you dealing with CSV files that uses CR line breaks?
I believe there are people here who are dealing with CSV files import on the daily basis, and since Excel is a really popular tool there ...
#how-to-question
10 18614 17
New
johnnyicon
Questions & Help>Questions

How do I use the Postgres JSONB / Postgrex JSON extension?
Hi all, I’ve just started learning Elixir and Phoenix Framework, so please pardon my n00bness at this stage. I’m trying to use Postgres...
#ecto
22 17673 9
New
JakeBecker
Chat & Discussions>Discussions

ElixirLS - the Elixir Language Server
TL;DR: I’ve just released an implementation of Microsoft’s IDE-independent Language Server Protocol for Elixir. It adds language support ...
#elixir-ls
1144 53690 245
New
josevalim
Official Elixir>Proposals

Behaviours, defoverridable and implementations
Hi everyone, One of the features added to Elixir early on to help integration with Erlang code was the idea of overridable function defi...
#official-elixir-proposal
111 22967 35
New
aalberti333
Questions & Help>Questions

Enum.map over list of key/value pairs with a map as the value
As the title describes, I’m trying to run Enum.map() over a list of key/value pairs, where the value is a map. My data looks like this: ...
#enummap
7 19866 6
New
klo
Chat & Discussions>Discussions

Concat/appending lists
Got a question about when to concat vs. prepending items to list then reversing to achieve appending. So i know lists boil down to [1 | ...
#erlang
20 15629 11
New
axelson
Chat & Discussions>Wikis

Emacs - Elixir Setup Configuration Wiki
This post is a wiki (feel free to hit the edit button near the bottom right of this post to add your own changes!) This post collects co...
#spacemacs#wiki#emacs#code-editors#language-server-protocol
239 47930 226
New
openscript
Questions & Help>Questions

How to set up the Elixir SDK in Intellij IDEA with the intellij-elixir plugin?
Hello! Sorry for this astonishing simple question, but I’m really stuck. I try to set up the intellij-elixir plugin, but I don’t know ho...
17 23170 9
New
vonH
Questions & Help>Questions

Why would I choose Elixir as a general purpose programming language?
In asking this question I am more interested about the expressiveness of the language itself and less concerned about the availability of...
#functional-programming#use-cases
65 34961 13
New
Back to top

Learning Resources>Coding Challenges

Resources Challenges ❯

Latest on Elixir Forum

Elixir Forum ❯

Sponsor Spotlight

EEF

Supporting innovation across the BEAM ecosystem.

Our Sponsors

Dashbit

Build Elixir applications with speed and confidence.

EEF

Supporting innovation across the BEAM ecosystem.

Coders51

We build reliable cloud platforms for business-critical systems.

AppSignal

Catch errors, track performance, monitor hosts and more.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

Pragmatic Bookshelf

Practical resources that improve the lives of professional developers.

Manning

Develop your skills with books, videos, and courses.

WyewWorks

Enabling companies to succeed by building software people love.

Pragmatic Studio

Courses that'll move you from confusion to "Aha, now I get it!"

View all our sponsors ❯

Categories:

Sub Categories:

Forums

Popular Tags

Our Sponsors

Dashbit

Build Elixir applications with speed and confidence.

EEF

Supporting innovation across the BEAM ecosystem.

Coders51

We build reliable cloud platforms for business-critical systems.

AppSignal

Catch errors, track performance, monitor hosts and more.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

Pragmatic Bookshelf

Practical resources that improve the lives of professional developers.

Manning

Develop your skills with books, videos, and courses.

WyewWorks

Enabling companies to succeed by building software people love.

Pragmatic Studio

Courses that'll move you from confusion to "Aha, now I get it!"

View all our sponsors ❯

We're in Beta

About us Mission Statement