https://adventofcode.com/ :sunglasses:
https://github.com/Bogdanp/awesome-advent-of-code
вот эти прогеры интересно решают:
https://github.com/juanj/AdventOfCode2020 - Swift
https://github.com/NoMod-Programming/Advent-of-Code-2020 - Python
https://github.com/0x8b/aoc-2020-rb - Ruby
https://github.com/vuryss/aoc-php - PHP
https://github.com/gugod/advent-of-code - Raku
https://github.com/mscha/aoc - Raku
https://github.com/skbkontur/AoC2020 - на разных языках
Разбор задач - https://www.youtube.com/playlist?list=PLc82OEDeni8RuE-PRirh1sgsfmaB4ai_q