The goal wasn't to memorize specific problems, but to be able to code a BFS/Union-Find/whatever without really thinking about it - freeing me up to think about the problem-specific edge cases.
I thought it would be nice to do this directly in the browser, so I made an extension over the weekend. It's free, open-source, with no signups/logins/tracking/etc. Your data is just stored in your browser and you can import/export/reset as you see fit.
I should mention that I used (and highly recommend!) the awesome ts-fsrs library: https://github.com/open-spaced-repetition/ts-fsrs
Thanks for reading!