aofcode advent of code solutions 2015 ⭐⭐ adv15.hs 2016 ⭐⭐ adv16.hs 2017 ⭐⭐ adv17.hs 2018 ⭐⭐ adv18.hs 2019 ⭐⭐ adv19.py 2020 ⭐⭐ adv20.py 2021 ⭐⭐ adv21.rb 2022 ⭐⭐ adv22.rb