Loading collection data...
Collections are a way for you to organize kata so that you can create your own training routines. Every collection you create is public and automatically sharable with other warriors. After you have added a few kata to a collection you and others can train on the kata contained within the collection.
Get started now by creating a new collection.
Rust issue. Instructions expect to return unsigned -1 for no available solution, check is for None in this case.
Submitted before actually finishing, I don't think it even passes but somehow it submitted. OOPS.