public Sequence<E> Riduci()
    {
         NodeSequence<E> seq = new NodeSequence<E>();
         if(size() < 1)
             return null;
         E elem = atIndex(0).element();
         seq.addLast(elem);
         for(int i = 1; i < size(); i++)
         {
             E toCmp = atIndex(i).element();
             if(!elem.equals(toCmp))
             {
                 elem = toCmp;
                 seq.addLast(elem);
             }
         }
         return seq;
    }