You can solve it in any way, and description does not need to provide a hint for solvers unless the task is some sort of puzzle or having complex algorithms

I would say "try to call libraries to do the work for you" as this is only an 8kyu level puzzle, and on top of that "reinventing the wheel is bad, mmmkay"

If they do not want you to attempt to use those libraries, the test cases are able to block that stuff.

I agree that the description is too short.

@anter69: No because:

All numbers in will be positive integers.

I wouldn't call this an issue, perhaps a suggestion. And probably history :-)

I feel the same way. I did my solution with only the library that was given to us and I feel kind of misled after looking at the top solutions.