Bzoj 1002 [fjoi 2007]

------------------------- Mengmeng da split line -------------------------

The question is easy to understand, and the data scope is not big. Of course, the violent person can be stuck.

When n = 1, it is obviously one of the following:

At n = 2, there are five (Some people think there are three, please clarify)

In fact, it is easy to see that recursion can solve this problem.

Select a situation. For example (2-Rotavirus)

Insert a vertex ..

How to push to several situations (3-Rotavirus?

This is an ideal situation.

Bzoj 1002 [fjoi 2007]