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Hackers’ Crackdown
Input: Standard Input
Output: Standard Output
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 finds 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, find the maximum number of services that the hacker can damage.
Input
There will be multiple test cases in the input file. A test case begins with an integer N (1<=N<=16), the number of nodes in the network. The nodes are denoted by 0 to N - 1. Each of the following N lines describes the neighbors of a node. Line i (0<=i<N)represents the description of node i. The description for node i starts with an integer m (Number of neighbors for node i), followed bym integers in the range of 0 to N - 1, each denoting a neighboring node of node i.
The end of input will be denoted by a case with N = 0. This case should not be processed.
Output
For each test case, print a line in the format, “Case X: Y”, where X is the case number & Y is the maximum possible number of services that can be damaged.
|
Sample Input |
Output for Sample Input |
|
3 2 1 2 2 0 2 2 0 1 4 1 1 1 0 1 3 1 2 0 |
Case 1: 3 Case 2: 2 |
题意：有n个电脑，一起执行1-n种工程，对于每台电脑，你有一次机会使其不能工作某一项工程，同时与它直接连接的电脑有收到该影响。如果一项工程没有电脑执行，那么这项工程就瘫痪了，问最多能瘫痪多少工程。
思路：首先每天电脑及其直接连接的先状压一下，表示使哪些瘫痪。S表示当前已经使哪些电脑瘫痪过的最大损坏工程数，如果S-S2可以瘫痪一个工程的话，那么dp[S]=max(dp[S],dp[S2]+1)。这里还有一个求子集的实现技巧见代码。
AC代码如下：
Hackers’ Crackdown - UVa11825 状压dp
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原文地址：http://www.cnblogs.com/yuyanbian/p/4179324.html
