There is no issue. In both cases you should return an empty array. The description only states what to do if you get an empty array as input, then you should always return an array without a single element, and with an array with only one element the answer is an empty array too.

My solution passes and it hasn't assignment.

it means it was expecting -1 but your code returns 0,
the problem is that in else if part you are not adding the temp_var, you are overriting it, you should do this instead "temp_var += b++"
other parts looks correct

Not a kata issue, that's your code's problem. See other solutions.