Some programming puzzles i solved using both c++ and Java to practice Java syntax coming from a c++ background.
Description and input for each puzzle can be found in the AdventOfCode19 website.
Advent of Code is an Advent calendar of small programming puzzles for a variety of skill sets and skill levels that can be solved in any programming language you like. People use them as a speed contest, interview prep, company training, university coursework, practice problems, or to challenge each other.
I also partecipated at AdventOfCode2020 solving way more challenges, repository at FedeWade/AdventOfCode2020.