Can someone tell me why he is not comparing to zero?
I mean, I really love this solution but i dont get it at all

This was a very challenging exercise.

After going down the wrong track for ages I've finally got it over the line. Seemed much harder than the other 5 kyu kata.

Same issue as iliuxe1409 below - please see answer by lechevalier !

Bazoogle has explained it perfectly. With your example, there is no ambiguity, so the specification is indeed to return 25689.

this one was harder for sure

Looks not difficult, but logically complex. It took hours to find a solution that works, yet I believe there must be a simpler approach.

fds?

Use spoiler flag next time, please.

OHh, I apreciate your idea.
I wish I could think as...

Therese problem in ramdom test cases. Kata is not provided piority of the procces. Some Cases for example [..0,0,1,2,3.] could be [0*2,1-3] and [..0,1-3,,] etc. Same code passed serveral tries later to submiting progress.

Oh I love this!

It was hard logic kata, with couple hours of different testing step by step)

not an issue.