Fixed.

Congratulations for keeping it up and becoming 1 dan!

Approved it myself.

Approved it myself.

Approved.

There’s absolutely no redundancy here—arrays are mutable by nature, and returning the array from arguments (in cases where N >= arr.length) can lead to unexpected behavior down the line. This practice is known as "defensive copying." If you make it a habit to run a red light just because there are no cars in sight, one day you’ll run it when there is a car. The same logic applies to code. Personally, I see no difference between writing production-level code and solving problems on Codewars—the rules are there for a reason, and they apply everywhere.

The input arrays are not unsorted.

In music theory, this is called an inverse interval.

is this some mathematical formula ? what's it called ?

maybe you should add some specifics about the expected behaviors, now. Because it's not really good (imo) to let the user dig into the tests to guess what the specs are.

edit: I don't fill like I "solved" the task, there...

Yeah not really. I was not bothered fixing it after dfhwze solved the challenge this way, but now there is two of you so maybe I need to prevent this way of accidentally solving it.

No, this is actually an unintended typo :) Not the worst one you'd see in real JIRA tickets :)

EDIT: I fixed the typo.

btw : so "sufucuent"? I don't get the pun (I guess there is?)

yeah, I'm not at home (in every possible meaning...), and the error messages are quite unreadable (because I'm not used to their formatting on smal windows: I didn't see some parts were hidden on the right, outside of view).

edit: I don't fill like I "solved" the task, there...