Is there a website with a large collection of exercises for theoretical computer science, sorted by topics? I know that many exercises can be found in different textbooks, I'm looking for an online database, preferably with hints/solutions included.
https://algomuse.net/ It's a kind of competition but problems are from research papers.
Here http://www.openproblemgarden.org/ Some problems have hints.
In this book, each chapter have some exercise: https://files.boazbarak.org/introtcs/lnotes_book.pdf