🎄 Advent of Code solutions in Elixir ⚗️

My personal solutions to AoC puzzles, in Elixir.

Caveats

• This repo contains spoilers, i.e. solutions to some of the puzzles. Use at your discretion.
• I'm brand new to Elixir, so this is largely practice for me. My solutions are likely not the best examples of "good" Elixir. If you see anything particularly egregious or have a cool way to improve a solution, feel free to submit an issue/PR.
• I do the challenges for fun, at my leisure. Plenty of the solutions are ugly/inefficient/incomplete. While I'm more than happy to take suggestions for existing solutions, please don't submit PRs for days I haven't completed yet (I don't want spoilers 😉). See https://twitter.com/ericwastl/status/1467243576966983685
• I don't intend to keep a clean commit history, so watch out if you get conflicts.

Usage

Solutions, tests, and input are structured by years and day.

• Solutions: lib/advent/y<YYYY>/d<DD>.ex, e.g. lib/advent/y2020/d01.ex
• Tests: test/advent/y<YYYY>/d<DD>_test.exs, e.g. test/advent/y2020/d01_test.exs
• Input: priv/puzzle_input/y<YYYY>/d<DD>.txt, e.g. priv/puzzle_input/y2020/d01.txt

Generate code scaffold for a given day

You can generate a scaffold for a given day by running:

mix aoc.gen.day <YYYY> <dd> [--session <TOKEN>]

For example, mix aoc.gen.day 2021 7 will generate

• lib/advent/y2021/d07.ex. Has two empty functions part_one/1 and part_two/1
• test/advent/y2021/d07_test.exs. Has 4 unit tests, 2 for each part. Each part has one for example input and another for file input
• priv/puzzle_input/y2021/d07.txt. An empty file to copy/paste your puzzle input into

The optional --session flag takes your web browser session token (you can retrieve if you inspect the web page while logged in). If provided, the task will attempt to download your input file.

Running tests

You can run all tests with mix test.

However, some of my solutions take an order of seconds. So I recommend testing a narrowed scope, e.g. a specific day or year. For example: mix test test/advent/y2021/ tests a specific year and mix test test/advent/y2021/d07_test.exs tests a specific day.

Further, some tests are tagged as long_running: true. These tests typically take longer than 10 seconds to complete on my laptop. Tests with this tag are excluded by default. To include these tests add --include long_running:true to your mix test command.

You can read more about mix test options here.

Completion matrix

• ⭐ just part one
• 🌟 both parts

Day	2015	2016	2017	2018	2019	2020	2021	2022	2023	2024
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							⭐

License

This project is licensed under the MIT License. See the LICENSE file for more details.