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.
considering the requirement, you have to find what kind of checks you do that are actually doomed to lead to a dead end. Prune your implementation from those cases. The reference solution (mine) passes the tests in 3,7s, compilation time included. So you're clearly missing one (or several) important "simplifications". ;)