hdu1054——Strategic Game（最小顶点覆盖+邻接表）-白红宇

hdu1054——Strategic Game（最小顶点覆盖+邻接表）

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发布时间：2019-05-10

本文共 1712 字，大约阅读时间需要 5 分钟。

Problem Description

Bob enjoys playing computer games, especially strategic games, but sometimes he cannot find the solution fast enough and then he is very sad. Now he has the following problem. He must defend a medieval city, the roads of which form a tree. He has to put the minimum number of soldiers on the nodes so that they can observe all the edges. Can you help him?

Your program should find the minimum number of soldiers that Bob has to put for a given tree.

The input file contains several data sets in text format. Each data set represents a tree with the following description:

the number of nodes

the description of each node in the following format

node_identifier:(number_of_roads) node_identifier1 node_identifier2 … node_identifier

node_identifier:(0)

The node identifiers are integer numbers between 0 and n-1, for n nodes (0 < n <= 1500). Every edge appears only once in the input data.

For example for the tree:

这里写图片描述

the solution is one soldier ( at the node 1).

The output should be printed on the standard output. For each given input data set, print one integer number in a single line that gives the result (the minimum number of soldiers). An example is given in the following table:

Sample Input

0:(1) 1

1:(2) 2 3

2:(0)

3:(0)

3:(3) 1 4 2

1:(1) 0

2:(0)

0:(0)

4:(0)

Sample Output

用最少的点来防卫周围的点，转换成二分图就是最小顶点覆盖的问题，当然前提是懂得这个转换。。。

另外数据有点大，不能用邻接矩阵，然而poj上用邻接表的还过不了。。

#include 
   
    #include 
    
     #include 
     
      #include 
      
       #include 
       
        #include 
        
         #include 
         
          #include 
          
           //#include 
           #include 
            
             #define INF 0x3f3f3f3f#define MAXN 1505#define Mod 10001using namespace std;bool vis[MAXN];int pre[MAXN],n; //匹配路径;vector
             
               map[MAXN];int find(int cur){ for(int i=0; i

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