thank you very much. I finally figured it out

It is a non capturing group, so you can group a set of characters and optionalise them. https://www.stefanjudis.com/today-i-learned/non-capturing-groups-in-regular-expressions/

that doesn't change anything

It's a magic))

Exactly.

No.

To OP,

in a test like 3 * 8 -> should return [3,3,2,1,1] right ?

Yes.

That makes sense. Thanks for the reply!

'test' is generally given by the author so you can edit the cases with examples you want to test (the lower right block of code can be edited if you want to test your own examples)
'attempt' checks your code against basic tests (usually with edge cases) and random tests (to ensure you didn't use only if-else statements to satisfy basic test)
this is how it usually works in most katas
so check your algo if it doesn't pass random tests.

Yeah that's what I get too. I passed all the test but when I "Attempt" my solution it fails. Not sure what's goint on with that. It shouldn't be allowed to pass all the "test", and then fail the "Attempt". That doesn't even make sense. I guess I have to go back to the drawing board. My algorithm is wrong.

Closing then.