My attempts at the Advent of Code 2024 challenges in PHP.

Solutions

Day	Name	Code	Time †	GitHub Action Output
01	Historian Hysteria	src/Day01.php	0.003701s
02	Red-Nosed Reports	src/Day02.php	0.014919s
03	Mull It Over	src/Day03.php	0.001430s
04	Ceres Search	src/Day04.php	0.018255s
05	Print Queue	src/Day05.php	3.213716s
06	Guard Gallivant	src/Day06.php	70.499905s
07	Bridge Repair	src/Day07.php	4.580957s
08	Resonant Collinearity	src/Day08.php	0.003884s
09	Disk Fragmenter	src/Day09.php	42.189519s
10	Hoof It	src/Day10.php	0.028195s
11	Plutonian Pebbles	src/Day11.php	0.016682s
12	Garden Groups	src/Day12.php	11.519407s
13	Claw Contraption	src/Day13.php	0.318790s
14	Restroom Redoubt	src/Day14.php	1.774646s
15	Warehouse Woes	src/Day15.php	0.039639s
16	Reindeer Maze	src/Day16.php	1,011.829665s
17	Chronospatial Computer	src/Day17.php	224.071246s
18	RAM Run	src/Day18.php	8.305735s
19	Linen Layout	src/Day19.php	0.142203s
20	Race Condition	src/Day20.php	13.676298s
21	Keypad Conundrum	src/Day21.php	TBD
22	Monkey Market	src/Day22.php	23.460746s
23	LAN Party	src/Day23.php	0.069283s

† The measured execution time in GitHub Actions

Installation

Installing on your machine

Installation with vary on each system. For a full environment the following dependencies should be installed:

• PHP 8.3
• Composer 2.6
• Xdebug 3.3

Installing with Docker

Using Docker avoids the complexity of installing the dependencies listed above.

Once Docker is installed, a Docker image can be built by running:

make docker-build

Once built, an interactive shell with the project directory mounted can be started by running:

make shell

How to run

Before running the code, the dependencies must be installed by running:

composer install

All puzzles can be executed by running:

php src/main.php

Individual puzzles can be executed by adding the day-number:

php src/main.php 01

The solutions can be benchmarked by adding the flag -b:

php src/main.php 01 -b

Why is the input data encrypted?

Note that the input data included in this repository have been encrypted, and exist purely for personal use. This is because the input data is the sole property of Advent of Code, and is not licensed for reproduction or distribution. To test with your own input, replace the contents of the file src/Day**.data with your own inputs from adventofcode.com.

If you somehow are in possession of the encryption key, you can unlock it using git-crypt by running:

echo "${BASE64_ENCODED_KEY}" | base64 -d | git-crypt unlock -

How to develop

As mentioned above, the code for each puzzle can be run individually. But this project has additional tools to help with development.

Generate Quiz Files

Some files have to be generated for every new quiz day. Those files can be automatically generated.

make generate 01 'name of quiz'

Tests

Test-driven-development using unit tests can help with solving a puzzle by ensuring individual functions work as expected. Tests can be added in tests/Unit/* and run using PHPUnit. The flags --testdox and --colors can help make the output more legible:

vendor/bin/phpunit tests/Unit/Day01Test.php --testdox --colors

This can be run quickly for all tests from the Makefile:

make tests

Note that some of the test data includes sample data from adventofcode.com, which have been encrypted for the same legal reasons mentioned above in "Why is the input data encrypted?". These tests will be skipped when attempting to run the tests.

Linting & Static Analysis

Following code standards can help make the code more legible and running static analysis tools can spot issues in the code. This project comes with PHP CodeSniffer and Psalm:

vendor/bin/phpcs -p --standard=PSR12 src/ tests/
vendor/bin/psalm --show-info=true

These can be run quickly from the Makefile:

make lint