zoukankan      html  css  js  c++  java
  • HDU 4587 B

    B - TWO NODES
    Time Limit: 20 Sec

    Memory Limit: 256 MB

    题目连接

    http://acm.hust.edu.cn/vjudge/contest/view.action?cid=87326#problem/B

    Description

    Suppose that G is an undirected graph, and the value of stab is defined as follows: 

    Among the expression,G -i, -j is the remainder after removing node i, node j and all edges that are directly relevant to the previous two nodes. cntCompent is the number of connected components of X independently. 
    Thus, given a certain undirected graph G, you are supposed to calculating the value of stab.
     

    Input

    The input will contain the description of several graphs. For each graph, the description consist of an integer N for the number of nodes, an integer M for the number of edges, and M pairs of integers for edges (3<=N,M<=5000). 
    Please note that the endpoints of edge is marked in the range of [0,N-1], and input cases ends with EOF.

    Output

    For each graph in the input, you should output the value of stab.

    Sample Input

    4 5
    0 1
    1 2
    2 3
    3 0
    0 2

    Sample Output

    HINT

    题意

    一个图,让你删除两个点之后,连通块最多有多少个

    题解

    枚举第一个点,然后跑tarjan求割点就好了

    代码:

    #include <iostream>
    #include <cstdio>
    #include <cstring>
    
    using namespace std;
    
    const int N=10010;
    int dfn[N],low[N],pre[N],to[N],nxt[N],vis[N],sum[N],cnt,tm,ans,tot,ret,aim,n,m;
    
    void makeedge(int a,int b)
    {
        to[cnt]=a;nxt[cnt]=pre[b];pre[b]=cnt++;
        to[cnt]=b;nxt[cnt]=pre[a];pre[a]=cnt++;
        return ;
    }
    
    void dfs(int x,int fa)
    {
        dfn[x]=tm;
        low[x]=tm++;
        vis[x]=1;
        sum[x]=0;
        for(int p=pre[x];p!=-1;p=nxt[p])
        {
            if(to[p]!=aim&&to[p]!=fa)
            {
                int y=to[p];
                if(!vis[y])
                {
                    vis[y]=1;
                    dfs(y,x);
                    low[x]=min(low[y],low[x]);
                    if(low[y]>=dfn[x]) sum[x]++;
                }
                else
                {
                    low[x]=min(low[x],dfn[y]);
                }
            }
        }
        if(x==fa) sum[x]--;
        if(ans<sum[x]) ans=sum[x];
        return ;
    }
    
    void solve()
    {
        ans=-1;tot=0;
        memset(vis,0,sizeof(vis));
        for(int i=1;i<=n;i++)
            if(!vis[i]&&i!=aim)
            {
                tm=0;
                dfs(i,i);
                tot++;
            }
        if(ret<ans+tot+2) ret=ans+tot+2;
     //   cout<<ans<<" "<<tot<<" "<<ans+tot+2<<endl;
        return ;
    }
    
    int main()
    {
        while(~scanf("%d%d",&n,&m))
        {
        memset(pre,-1,sizeof(pre));
        memset(dfn,0,sizeof(dfn));
        memset(low,0,sizeof(low));
        memset(vis,0,sizeof(vis));
        memset(sum,0,sizeof(sum));
        cnt=0;ans=0;tot=0;tm=0;ret=0;
        for(int i=1;i<=m;i++)
        {
            int a,b;
            scanf("%d%d",&a,&b);
            a++,b++;
            makeedge(a,b);
        }
        for(int i=1;i<=n;i++)
        {
            aim=i;
            solve();
        }
        printf("%d
    ",ret-2);
        }
        return 0;
    }
  • 相关阅读:
    Spring Boot 配置文件 bootstrap vs application 到底有什么区别?
    一份完整的 Java 成神路线图,值得收藏!
    12 岁开始学编程,17 岁总结了 7 个重要教训!
    想成为顶尖 Java 程序员?先过了下面这些问题!
    Dubbo面试20问!这些题你都遇到过吗?
    yum安装出现No package crontabs available解决办法
    表结构设计方法
    后端token认证模板
    vue 用户登录 路由拦截 vuex cookie
    pyharm无法安装包的问题
  • 原文地址:https://www.cnblogs.com/qscqesze/p/4721849.html
Copyright © 2011-2022 走看看