zoukankan      html  css  js  c++  java
  • HDU 1054 Hungary

    Strategic Game

    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
    or
    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:

    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
    4
    0:(1) 1
    1:(2) 2 3
    2:(0)
    3:(0)
    5
    3:(3) 1 4 2
    1:(1) 0
    2:(0)
    0:(0)
    4:(0)

    Sample Output
    1
    2

    一定要注意 不能把first数组或者fa数组初值设成零,因为这里有0这个点。。因为这个查了好久的错。。。。

    #include <cstdio>
    #include <cstring>
    #include <algorithm>
    using namespace std;
    int n,tot=0,first[1505],nxt[1500*1505*2],v[1500*1500*2],fa[1505],ans=0;
    bool vis[1505];
    inline void add(int xx,int yy)
    {
        v[tot]=yy;
        nxt[tot]=first[xx];
        first[xx]=tot++;
    }
    bool dfs(int x)
    {
        for(int i=first[x];~i;i=nxt[i])
            if(!vis[v[i]]){
                vis[v[i]]=1;
                if(fa[v[i]]==-1||dfs(fa[v[i]])){
                    fa[v[i]]=x;return true;
                }
            }
        return false;
    }
    int main()
    {
        while(scanf("%d",&n)!=EOF)
        {
            memset(first,-1,sizeof(first));
            memset(fa,-1,sizeof(fa));
            tot=ans=0;
            for(int i=0;i<n;i++){
                register int xx,yy,zz;
                scanf("%d:(%d)",&xx,&yy);
                for(int j=1;j<=yy;j++){
                    scanf("%d",&zz),add(zz,xx),add(xx,zz);
                }
            }
            for(int i=0;i<n;i++){
                memset(vis,0,sizeof(vis));
                if(dfs(i)==1)ans++;
            }
            printf("%d
    ",ans/2);
        }
    } 

    这里写图片描述

  • 相关阅读:
    ASP.NET 2.0 web.config数据库连接设置与读取
    一句话影评
    百度地图api示例
    centos5.8 误改/etc/fstab后导致系统进不去 解决办法
    Nginx Gzip 压缩配置
    数据库设计的三大范式
    CentOS 6.0下vncserver安装配置
    MySQL配置文件my.cnf设置
    Linux下zip加密压缩
    keepalived的log
  • 原文地址:https://www.cnblogs.com/SiriusRen/p/6532478.html
Copyright © 2011-2022 走看看