Advent of Code is an Advent calendar of small programming puzzles for a variety of skill levels that can be solved in any programming language you like. People use them as interview prep, company training, university coursework, practice problems, a speed contest, or to challenge each other.
language of choice: go
Really great collection of puzzles this year. Very proud of how much farther I was able to come this time (tapping out at day 21 last year)
All solutions run in a total of 8.029s