The missing piece is often the solution book which can be difficult to come by. like leetcode and other problem assesors, you learn a lot by trying, failing, a

The missing piece is often the solution book which can be difficult to come by. like leetcode and other problem assesors, you learn a lot by trying, failing, and getting an explanation of where it went wrong. Would be pretty useful to have an online platform for worked textbook problems from arbitrary textbooks.