BZOJ 1391 order

为什么这么慢呢。。。。

跑得如此持久。。。。。

大概就是一个最大权闭合子图的构图。

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<queue>
#define inf 1000000007
#define maxv 2500
#define maxe 3000050
using namespace std;
int n,m,k,x,y,g[maxv],nume=1,s,t,dis[maxv],sum=0,max_flow=0;
struct edge
{
    int v,f,nxt;
}e[maxe];
queue <int> q;
int read()
{
    char ch;int data=0,f=1;
    while (ch<'0' || ch>'9')
    {
        if (ch=='-') f=-1;
        ch=getchar();
    }
    while (ch>='0' && ch<='9')
    {
        data=data*10+ch-'0';
        ch=getchar();
    }
    return data*f;
}
void addedge(int u,int v,int f)
{
    e[++nume].v=v;e[nume].f=f;
    e[nume].nxt=g[u];g[u]=nume;
    e[++nume].v=u;e[nume].f=0;
    e[nume].nxt=g[v];g[v]=nume;
}
bool bfs()
{
    while (!q.empty()) q.pop();
    for (register int i=s;i<=t;i++) dis[i]=inf;
    dis[s]=0;q.push(s);
    while (!q.empty())
    {
        int head=q.front();q.pop();
        for (register int i=g[head];i;i=e[i].nxt)
        {
            int v=e[i].v;
            if (e[i].f<=0) continue;
            if (dis[v]>dis[head]+1)
            {
                dis[v]=dis[head]+1;
                q.push(v);
            }
        }
    }
    return dis[t]!=inf;
}
int dinic(int x,int low)
{
    if (x==t) return low;
    int ret=0;
    for (register int i=g[x];low && i;i=e[i].nxt)
    {
        int v=e[i].v;
        if ((e[i].f>0) && (dis[v]==dis[x]+1))
        {
            int dd=dinic(v,min(low,e[i].f));
            e[i].f-=dd;e[i^1].f+=dd;
            ret+=dd;low-=dd;
        }
    }
    if (!ret) dis[x]=inf;
    return ret;
}
int main()
{
    n=read();m=read();s=0;t=n+m+1;
    for (register int i=1;i<=n;i++)
    {
        x=read();k=read();sum+=x;addedge(s,i,x);
        for (register int j=1;j<=k;j++)
        {
            x=read();y=read();
            addedge(i,x+n,y);
        }
    }
    for (register int i=1;i<=m;i++)
    {
        x=read();
        addedge(i+n,t,x);
    }
    while (bfs())
        max_flow+=dinic(s,inf);
    printf("%d\n",sum-max_flow);
    return 0;
}