How is it possible to get 0 out of 10

Cas

I'm back from the exam review, i've seen what was wrong...
i solved the problems with correct algorithms but for a different data structure, say. I had to implement (using pen and paper) add, get and clone methods for a fifo queue. Each element in the queue was a linkable wrapper, as the Sun's LinkedList implementation uses. An element has a reference to the
next element as follows
null <- [first element]<-...<-[last element]
note that with "next", they were referencing the next element that would be returned by the get method, instead of the next element of the queue, that wasn't clear at all on the exam, so i understood that the linkables were linked the other way round:
[first element]->...->[last element]->null
referencing the _next_ element on the queue, so none of methods didn't worked for them and i got the lowest callification, not a sigle point