zoukankan      html  css  js  c++  java
  • HDOJ 3549 Flow Problem



    Flow Problem

    Time Limit: 5000/5000 MS (Java/Others)    Memory Limit: 65535/32768 K (Java/Others)
    Total Submission(s): 5713    Accepted Submission(s): 2670


    Problem Description
    Network flow is a well-known difficult problem for ACMers. Given a graph, your task is to find out the maximum flow for the weighted directed graph.
     

    Input
    The first line of input contains an integer T, denoting the number of test cases.
    For each test case, the first line contains two integers N and M, denoting the number of vertexes and edges in the graph. (2 <= N <= 15, 0 <= M <= 1000)
    Next M lines, each line contains three integers X, Y and C, there is an edge from X to Y and the capacity of it is C. (1 <= X, Y <= N, 1 <= C <= 1000)
     

    Output
    For each test cases, you should output the maximum flow from source 1 to sink N.
     

    Sample Input
    2
    3 2
    1 2 1
    2 3 1
    3 3
    1 2 1
    2 3 1
    1 3 1
     

    Sample Output
    Case 1: 1
    Case 2: 2
     

    Author
    HyperHexagon
     

    Source
     

    Recommend
    zhengfeng
     



    #include <iostream>
    #include <cstdio>
    #include <cstring>
    #include <queue>

    using namespace std;

    const int INF=0x3f3f3f3f;
    const int MaxV=10000,MaxE=11000;

    struct Edge
    {
        int to,next,flow;
    };

    Edge E[MaxE+10];
    int Size,Adj[MaxV+10],src,sink,dist[MaxV+10];
    bool vis[MaxV+10];

    void Init()
    {
        Size=0;
        memset(Adj,-1,sizeof(Adj));
    }

    void Add_Edge(int u,int v,int c)
    {
        E[Size].to=v;
        E[Size].next=Adj;
        E[Size].flow=c;
        Adj=Size++;
        E[Size].to=u;
        E[Size].next=Adj[v];
        E[Size].flow=0;
        Adj[v]=Size++;
    }

    void bfs()
    {
        memset(dist,0,sizeof(dist));
        memset(vis,false,sizeof(vis));
        queue<int> q;
        q.push(src);  vis[src]=true;
        while(!q.empty())
        {
            int u=q.front(); q.pop();
            for(int i=Adj;~i;i=E.next)
            {
                int v=E.to;
                if(E.flow&&!vis[v])
                {
                    vis[v]=true;
                    q.push(v);
                    dist[v]=dist+1;
                }
            }
        }
    }

    int dfs(int u,int delta)
    {
        if(u==sink)
        {
            return delta;
        }
        else
        {
            int ret=0;
            for(int i=Adj;~i&&delta;i=E.next)
            {
                int v=E.to;
                if(E.flow&&dist[v]==dist+1)
                {
                    int dd=dfs(v,min(delta,E.flow));
                    E.flow-=dd; E[i^1].flow+=dd;
                    delta-=dd; ret+=dd;
                }
            }
            return ret;
        }
    }

    int maxflow()
    {
        int ret=0;
        while(true)
        {
            bfs();
            if(vis[sink]==falsereturn ret;
            ret+=dfs(src,INF);
        }
    }

    int main()
    {
        int T,cas=1;
        scanf("%d",&T);
        while(T--)
        {
            int n,m;
            Init();
            scanf("%d%d",&n,&m);
            for(int i=0;i<m;i++)
            {
                int a,b,c;
                scanf("%d%d%d",&a,&b,&c);
                Add_Edge(a,b,c);
            }
            src=1,sink=n;
            printf("Case %d: %d ",cas++,maxflow());
        }

        return 0;
    }
    * This source code was highlighted by YcdoiT. ( style: Codeblocks )
  • 相关阅读:
    重置主键自增
    tp5引入第三方类库
    判断浏览器是否是手机端
    网站二级域名的配置
    阿里云服务器php环境的搭建
    备忘录——二维码
    (3) 编写一个截取字符串的函数,输入一个字符串和字节数,输出按字节书截取的字符串,但是要保证汉字不能截半个
    (2) 假设字符串类似这样的aba和aab就相等,现在随便给你二组字符串,请编程比较他们看是否相等
    (1) 一个字符串,根据输入参数m,找出字符串的m个字符的所有字符串
    Windows下MySQL双向同步及环形同步的实现
  • 原文地址:https://www.cnblogs.com/CKboss/p/3350883.html
Copyright © 2011-2022 走看看