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Re:谁用Dinic过的这题。。?我头回遇到Dinic也超时的

Posted by liutun at 2015-05-08 10:55:23 on Problem 2987
In Reply To:谁用Dinic过的这题。。?我头回遇到Dinic也超时的 Posted by:heimengnan at 2010-02-27 15:54:23
#include<iostream>
#include<queue>
#include<cstring>
#include<cstdio>
#include<climits>
#define MAXE 65100*2
#define MAXP 5100
#define Max(a,b) a>b?a:b
#define Min(a,b) a<b?a:b
using namespace std;
struct Edge
{
    long long int s,t,next;
    long long f;
} edge[MAXE];
long long int head[MAXP];
long long int cur[MAXP];
long long int pre[MAXP];
long long int stack[MAXE];
long long int dep[MAXP];
long long int ent;
long long int n,m,s,t,cot;
void add(long long int start,long long int last,long long int f)
{
    edge[ent].s=start;
    edge[ent].t=last;
    edge[ent].f=f;
    edge[ent].next=head[start];
    head[start]=ent++;
    edge[ent].s=last;
    edge[ent].t=start;
    edge[ent].f=0;
    edge[ent].next=head[last];
    head[last]=ent++;
}
bool bfs(long long int S,long long int T)
{
    memset(pre,-1,sizeof(pre));
    pre[S]=0;
    queue<long long int>q;
    q.push(S);
    while(!q.empty())
    {
        long long int temp=q.front();
        q.pop();
        for(long long int i=head[temp]; i!=-1; i=edge[i].next)
        {
            long long int temp2=edge[i].t;
            if(pre[temp2]==-1&&edge[i].f)
            {
                pre[temp2]=pre[temp]+1;
                q.push(temp2);
            }
        }
    }
    return pre[T]!=-1;
}
long long int dinic(long long int start,long long int last)
{
    long long int flow=0,now;
    while(bfs(start,last))
    {
        long long int top=0;
        memcpy(cur,head,sizeof(head));
        long long int u=start;
        while(1)
        {
            if(u==last)//如果找到终点结束对中间路径进行处理并计算出该流
            {
                long long int minn=INT_MAX;
                for(long long int i=0; i<top; i++)
                {
                    if(minn>edge[stack[i]].f)
                    {
                        minn=edge[stack[i]].f;
                        now=i;
                    }
                }
                flow+=minn;
                for(long long int i=0; i<top; i++)
                {
                    edge[stack[i]].f-=minn;
                    edge[stack[i]^1].f+=minn;
                }
                top=now;
                u=edge[stack[top]].s;
            }
            for(long long int i=cur[u]; i!=-1; cur[u]=i=edge[i].next) //找出从u点出发能到的边
                if(edge[i].f&&pre[edge[i].t]==pre[u]+1)
                    break;
            if(cur[u]==-1)//如果从该点未找到可行边,将该点标记并回溯
            {
                if(top==0)break;
                pre[u]=-1;
                u=edge[stack[--top]].s;
            }
            else//如果找到了继续运行
            {
                stack[top++]=cur[u];
                u=edge[cur[u]].t;
            }
        }
    }
    return flow;
}
void dfs(long long int u)
{
    cot++;
    dep[u]=1;
    for(long long int i=head[u];i!=-1;i=edge[i].next)
    {
        long long int v=edge[i].t;
        if(!dep[v]&&edge[i].f>0)
        {
            dfs(v);
        }
    }
}
int main()
{
    while(~scanf("%lld%lld",&n,&m))
    {
        s=0;
        t=n+1;
        ent=0;
        long long int cost,u,v;
        long long int ans=0;
        memset(head,-1,sizeof(head));
        for(int i=1; i<=n; i++)
        {
            scanf("%lld",&cost);
            if(cost>0)
            {
                add(s,i,cost);
                ans+=cost;
            }
            else add(i,t,-cost);
        }
        for(int i=1; i<=m; i++)
        {
            scanf("%lld%lld",&u,&v);
            add(u,v,INT_MAX);
        }
        memset(dep,0,sizeof(dep));
        long long int flow=dinic(s,t);
        cot=0;
        dfs(s);
        printf("%lld ",cot-1);
        printf("%lld\n",ans-flow);
    }
    return 0;
}

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