Advent of Code

Advent of Code is an 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.

In the Cloud Native ecosystem, Go has emerged as the language of choice. As a Site Reliability Engineer, knowing how to write software in Go is a useful skill.

Whether you are new to Go or have already written countless lines of it, this repository aims at giving you everything you need to improve.

Getting started

First and foremost, go to the Advent of Code website and log in.

To get started on a solution, clone this repository:

git clone git@github.com:busser/adventofcode.git
cd adventofcode

Remove existing solutions to start from scratch:

rm -r y*

Build the adventofcode command-line tool:

make build

Get started on your first puzzle:

bin/adventofcode scaffold --day 1 --workdir "$(pwd)"

The command above will create a package where your code will go. Your next steps should be:

1. Implement your solution in the solution.go file. Use this command to test it:

   go test ./y2021/d01 -run ExamplePartOne

2. Once you think you have found the answer to the problem, submit it on the adventofcode.com website. If it's the right answer, congrats!

3. Update your tests by adding the answer to ExamplePartOne in solution_test.go.

4. Repeat steps 1 to 3 for the second part of the Advent of Code problem.

5. Now that you have finished, run all tests to make sure everything is ready for your pull request:

   make test

Once you are done with the first day of the Advent of Code, have a look at the Configuration section below on how you can configure the adventofcode CLI, or the Tests and benchmarks section for tips on how to measure your solution's performance.

Scaffolding

The adventofcode can help you get started quickly on your solution to the daily Advent of Code problems. The scaffold subcommand builds the following for you:

• A new package to write your solution in;
• A solution.go file with a basic code skeleton to get started quickly;
• A solution_test.go file with basic unit tests and benchmarks, for when you have found the answer to the daily problem;

It can also download your input for the day's problem, granted you have provided your adventofcode.com session cookie (see Session cookie for details).

Session cookie

When logged in to the adventofcode.com website, your browser has a cookie called session. Retrieve this cookie's value and provide it to the adventofcode CLI to automatically download your input for the day.

Helpers

This repository includes a helpers package with useful functions for implementing solutions to Advent of Code problems. Feel free to use any of them.

For examples on how to use them, look for functions that start with Example. These are actually unit tests, so you can be sure that they work as described.

Tests and benchmarks

The scaffolding provided by the adventofcode CLI includes unit tests and benchmarks. To run them, make sure they are properly uncommented in the solution_test.go file, then run these commands:

# Run all units tests
go test ./y2022/d01
# Run all benchmarks
go test ./y2022/d01 -bench . -benchmem -cpu 1,2,4,8

Configuration

To configure the adventofcode CLI, you can use flags, environment variables, or a configuration file.

Flags

The CLI is entirely configurable with flags. For a list of available flags, use these commands:

adventofcode --help
adventofcode scaffold --help

Environment variables

You can replace any flag in the adventofcode CLI with an environment variable. Environment variables must simply start with ADVENTOFCODE_. For example, you can replace the --workdir flag by setting the ADVENTOFCODE_WORKDIR variable.

If you have direnv installed, you can add a .envrc file to the adventofcode directory that looks like this:

export ADVENTOFCODE_WORKDIR="$(git rev-parse --show-toplevel)"
export ADVENTOFCODE_COOKIE="abcdef0123456789..."

Configuration file

The adventofcode CLI automatically looks for a configuration file located in your home directory: $HOME/.adventofcode.yaml. In this file, you can set values for any flag. For example, your configuration file could look like this:

workdir: /Users/arthur/workspace/adventofcode
cookie: abdefg0123456789...

Troubleshooting

If you encounter any problems while using the adventofcode CLI, let us know with a GitHub issue.

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Made with 💜 by @busser.