On December 1st the 2018 edition of Advent of Code will start. For those who don’t know what Advent of Code is: It is a programming competition where the authors release one programming problem every day at midnight EST/UTC-5 (6.00 in Germany).
The difficulty of the problems varies every day and it’s mostly about developing algorithms based on detailed descriptions. If you’re interested in how problems look like, check AOC 2017. You can implement your solution in any language you prefer. You don’t submit your code, but only the response of your algorithm to an input that is given to you on the problem description (this input is different for every user, so you cannot just steal it from others).