【题解】Uva11825 Hacker’s Crackdown 水题

题目描述：
Miracle Corporations has a number of system services running in a distributed computer system which
is a prime target for hackers. The system is basically a set of
N
computer nodes with each of them
running a set of
N
services. Note that, the set of services running on every node is same everywhere
in the network. A hacker can destroy a service by running a specialized exploit for that service in all
the nodes.
One day, a smart hacker collects necessary exploits for all these
N
services and launches an attack
on the system. He nds a security hole that gives him just enough time to run a single exploit in each
computer. These exploits have the characteristic that, its successfully infects the computer where it
was originally run and all the neighbor computers of that node.
Given a network description, nd the maximum number of services that the hacker can damage.
题目分析：
将模型建成集合，之后就容易想到状压 DP 啦。