A few questions (Array, Lastval, Siblings)

My last three questions for now, thankz

1. Array as parameter of function

Is it possible to pass to a function as a parameter an array (of string, or integer, or any type) without
having to declare explicity a type for each one??

2. How can i obtain the lastval of a sequence?, something similar than namesequence.NEXTVAL but giving back teh lastval?


3. CONNECT BY:
- Is it possible to use distinct or Group by when using SIBLINGS to order the tree???