Advent of Code in Kotlin
Pretty much what the name says.
Usage
First, you'll need to grab your session cookie from the Advent of Code site by going to Developer Tools > Storage > Cookies > https://adventofcode.com and selecting the value labeled session, and store it in a file named .session in the project root folder. This allows inputs to be downloaded automatically, but must be refreshed after a month.
Then, for each year open src and simply copy the year0000 folder and rename it, and do the same for each day with day00. Change the package name as well to prevent conflicts, and ensure it starts with yearYYYY.dayDD, as this is required for the input downloader to correctly autodetect the correct date.
From there, open up the day's Main.kt file, and solve! Run the main() function from your IDE when you're done. (If you are using VSCode or anything else whose Kotlin support is based on the Kotlin Debug Adapter, see this issue.)