In 2015 I focused primarily on learning the quirks of python. Most of the code there are oneliners, sometimes even readable ones.
Readability was the goal of 2016. Achieved or not, that's for the reader to decide!
2017, the year of nothing in particular. Code, code, code...
If you want to learn something golfy and quirky head over to 2018. One liners galore, won't argue about the readability though, yuck. A cool solution to day 8.
2019, most fun year so far? Maybe because I solved all intcode puzzles before starting the mathy ones.
If you're new to programming; 2020 is your jam. Back to the basics year with a bit of number theory. Although I managed to crack the global leaderboard on the 90th position, my median position was 1391.
2021 was fun and games up to day 17, and a tough nut to crack from then on out. I managed to get on the leaderboard on days 5 and 22. My median position was 600, on 15 puzzles I was sub 300th.