Given a sequence of integers of length n, print the number of prefix permutations within it.

I don't think it should print the result. This should be changed.

The only performance tests are fixed, and they can be easily hardcoded allowing non-optimal solutions to pass.

I think must be test case like [-5,-3,-2,-4,-1] equal 3

Please, add details on the assumptions about the input array such as it containing only positive integers, without repetition, or add some tests.

Also precise input array could be large.