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.
For formatting information, see: https://docs.codewars.com/references/markdown
This comment is hidden because it contains spoiler information about the solution
Please remember to mark your post as having spoiler content next time. Your problem is related to x being declared with final keyword, you can't modify its value like that. You can simply return the value you were assigning to it, or remove final keyword.
You haven't mentioned what programming language you are using, and you gave no code example, so it is really hard to answer your question.
No idea what do you mean with that, check Solutions page, using x is possible.