Latest #advent-of-code Threads 
Why did the number of days per event change? It takes a ton of my free time every year to run Advent of Code, and building the puzzles ac...
New
defmodule Day12 do
def part1(input) do
{presents, regions} = parse(input)
regions
|> Enum.reject(fn region ->
...
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Graph traversals
Parse
graph =
puzzle_input
|> String.split("\n", trim: true)
|> Map.new(fn <<from::binary-3>> ...
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Well some of us wanted a difficulty spike - and today we got one :sweat_smile:
https://github.com/sevenseacat/advent_of_code/blob/main/l...
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We were all waiting for a (more) complex problem, and here it is, finally! As of now, it’s the only problem that has 3x more people who o...
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Nice little problem. The right data structure is half the solution!
defmodule Y2025.Day08 do
def pairs(enum) do
l = enum |> Enu...
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Part 1 took much more time than part 2. I started out by reusing my grid parsing function from day 4 and start coding before I had fully ...
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defmodule Day06 do
def part1(input) do
input
|> Enum.map(fn line ->
line
|> String.split(" ", trim: true)
...
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Easy puzzles two days in a row. I suspect tomorrow’s puzzle will not be that easy…
defmodule Day05 do
def part1(input) do
{ranges,...
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defmodule Day04 do
def part1(input) do
grid = parse(input)
Enum.count(removable(grid))
end
def part2(input) do
grid = ...
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This Week's Trending
This Month's Trending
Well some of us wanted a difficulty spike - and today we got one :sweat_smile:
https://github.com/sevenseacat/advent_of_code/blob/main/l...
New
This Year's Trending
Hello everyone!
This year is going to be shorter, but the difficulty will grow faster. Today I already feel that this is not standard “D...
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2025 Dec 03
Lobby
defmodule Joltage do
def parse_line(s) do
String.trim(s)
|> to_charlist()
|> Enum.map(fn ch -&g...
New
We were all waiting for a (more) complex problem, and here it is, finally! As of now, it’s the only problem that has 3x more people who o...
New
“When in doubt, use brute force.” – Ken Thompson
defmodule Day02 do
def part1(input) do
solve(input, &invalid_part1?/1)
end
...
New
Part 1 took much more time than part 2. I started out by reusing my grid parsing function from day 4 and start coding before I had fully ...
New
Easy puzzles two days in a row. I suspect tomorrow’s puzzle will not be that easy…
defmodule Day05 do
def part1(input) do
{ranges,...
New
AOC 2025 is right around the corner. Last year, my first year, I just started a raw Elixir application and manually created modules for e...
New
defmodule Day04 do
def part1(input) do
grid = parse(input)
Enum.count(removable(grid))
end
def part2(input) do
grid = ...
New
defmodule Day06 do
def part1(input) do
input
|> Enum.map(fn line ->
line
|> String.split(" ", trim: true)
...
New
Nice little problem. The right data structure is half the solution!
defmodule Y2025.Day08 do
def pairs(enum) do
l = enum |> Enu...
New
defmodule Day12 do
def part1(input) do
{presents, regions} = parse(input)
regions
|> Enum.reject(fn region ->
...
New
Graph traversals
Parse
graph =
puzzle_input
|> String.split("\n", trim: true)
|> Map.new(fn <<from::binary-3>> ...
New
Last Three Year's Trending
Nobody’s doing Advent of Code this year? :grinning_face_with_smiling_eyes:
I might do the first week or so.
For Day 1, first I solved i...
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Here is my solution for day 2 of Advent of Code:
https://github.com/bjorng/advent-of-code/blob/main/2024/day02/lib/day02.ex
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Setting this down for the night, as after a quick naive solve for quick part 1 I realize that part 2 is by design computationally expensi...
New
Here is my solution for day 1 of Advent of Code:
defmodule Day01 do
def part1(input) do
all = parse(input)
{first, second} = E...
New
Today is a brute-force day: advent-of-code-2024/lib/advent_of_code2024/day6.ex at main · ibarakaiev/advent-of-code-2024 · GitHub
Takes a...
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The second part of today’s puzzle is very misleading.
FYI, each of the ghosts has only one possible position that ends with a "Z" on its...
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I tried to use combinatorial to solve today’s puzzles but failed (my brain burned out :exploding_head:). In the end I just used brute for...
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Here’s my day 3 code
https://github.com/code-shoily/advent_of_code/blob/master/lib/2024/day_03.ex
This was quite easy. I was afraid Par...
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I spent 3 hours struggling in part 2, until I noticed a very basic mistake :joy:
Here’s my code:
https://github.com/Aetherus/advent-of-...
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I said I was on a break, but I took a sneak peak and it looked fun so…
Part 1 completes in half a millisecond with a single pass of the ...
New
Thought I’d kick today’s thread off!
Parsing
Enum rocks, so most of my code was actually in parsing input.
▶ Preprocessing input
Part 1...
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Here is my solution for day 4:
https://github.com/bjorng/advent-of-code/blob/main/2024/day04/lib/day04.ex
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Today’s problem is really tense. I don’t think I can do it without libgraph.
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Everything went smoothly today.
Nothing to change to solve part 2 because I already used memoization for part 1 (it looked like an AoC e...
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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: ...
New
Trending Over Three Years
This topic is about Day 1 of the Advent of Code 2021.
We have a private leaderboard (shared with users of Erlang Forums):
https://adven...
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Note by the Moderators: This topic is for general discussion about the Advent of Code 2018.
To prevent people from being spoiled about s...
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In General if the Enum.all? evaluates true that means all the elements in the given collection evaluates true for the given callback func...
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This topic is about Day 3 of the Advent of Code 2020 .
Thanks to @egze, we have a private leaderboard:
https://adventofcode.com/2020/le...
New
This topic is about Day 7 of the Advent of Code 2020 .
Thanks to @egze, we have a private leaderboard:
https://adventofcode.com/2020/le...
New
Note: This topic is to talk about Day 2 of the Advent of Code 2019 .
There is a private leaderboard for elixirforum members. You can joi...
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It is that time of the year again: Advent of Code 2022 :christmas_tree:
Day 1
Leaderboard:
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This topic is about Day 5 of the Advent of Code 2020 .
Thanks to @egze, we have a private leaderboard:
https://adventofcode.com/2020/le...
New
Hello, guys. I’m back again, but only for the weekends, maybe.
This topic is about Day 13 of the Advent of Code 2020 .
Thanks to @egze,...
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Note: This topic is to talk about Day 1 of the Advent of Code 2019.
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Hi, there :wave:
Today, I felt it was way more challenging! I went through part2 thanks to Agent based memoization (without memoization ...
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Note: This topic is to talk about Day 7 of the Advent of Code 2019 .
There is a private leaderboard for elixirforum members. You can joi...
New
Continuation of Advent of Code 2022:christmas_tree:, Day 1:
Day 2!
Leaderboard:
New
This topic is about Day 17 of the Advent of Code 2020 .
Thanks to @egze, we have a private leaderboard:
https://adventofcode.com/2020/l...
New
Note by the Moderators: This topic is to talk about Day 6 of the Advent of Code.
For general discussion about the Advent of Code 2018 an...
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