advent-of-code-kotlin

This repository contains a library to help solve the Advent of Code Challenges (https://adventofcode.com) in Kotlin. This library will get the puzzle input and example data from the website and also submit the results.

There are additional helper functions to work with vectors and do traversals through graphs.

At the moment this repository also contains my solutions for the puzzles; I will probably move them to a separate repository at some point.

Install and Run

No specific installation is needed, you only need a somewhat recent Java Runtime. I will not give any specific version constraints, but would recommend at least version 1.8.

The library is not yet available on Maven, so you need to check out or download the repository and add the source files to your project manually.

Puzzle inputs are different for each user, so the library needs your session token to get the puzzle inputs for your specific user. You can get the session token from your browser cookies after you are logged in on https://adventofcode.com. Check this post from Stackexchange for help. Then you need to create a file with path ~/.config/adventofcode/token containing the session token without whitespace or newlines. On Windows, the path will be C:\User\<username>\.config\adventofcode\token.

To use the library, implement a class containing the solution for a puzzle and create a Day object in the main function. This is shown in the following snippet:

class PartA : PartSolution() {
    lateinit var numbers: List<Int>

    override fun parseInput(text: String) {
        numbers = text.trim().split("\n").map { it.toInt() }.toList()
    }

    override fun getExampleAnswer(): String {
        return "7"
    }

    override fun compute(): String {
        return countIncreases().toString()
    }

    private fun countIncreases(): Int {
        return numbers.windowed(2).map { it[1] > it[0] }.count { it }
    }
}

class PartB : PartA() {
    ...
}

fun main() {
    Day(2021, 1, PartA(), PartB())
}

You should also have a Logback configuration file in your project's root folder or at a configured location.