Earlier or later every developer comes back to datastructures, algorithms and problems.
Some to prepare for a next step in their carrier, others out of curiousity and keep their brains sharp, somebody might even need it for work (it still happens, really!).
Sometimes it's just unstructured pieces of codes scattered across different laptop reincarnations left to rust in the basement, often it's online assessment platforms like leetcode or so.
And this one is my attempt to bring some structure just for me.