bzoj 1179: [Apio2009]Atm

/**************************************************************
    Problem: 1179
    User: lxy8584099
    Language: C++
    Result: Accepted
    Time:7020 ms
    Memory:58476 kb
****************************************************************/
 
/*
    缩点后dfs 途中更新答案 
*/
#include<queue>
#include<cstdio>
#include<cstring>
using namespace std;
const int N=500050;
struct pp {int u,v,nxt;} e[N]; 
int head[N],tot,n,m,o,a[N],st,maxn;
int sta[N],dfn[N],low[N],top,fa[N],dis[N];
bool vis[N],bar[N];
void add(int u,int v)
{
    e[++tot].nxt=head[u],head[u]=tot;
    e[tot].v=v;e[tot].u=u;
}
int min(int a,int b) {return a>b?b:a;} 
int max(int a,int b) {return a>b?a:b;} 
void tarjan(int u)
{
    vis[u]=1;sta[++top]=u;
    dfn[u]=low[u]=++tot;
    for(int j=head[u];j;j=e[j].nxt)
    {
        int v=e[j].v;
        if(!dfn[v])
        {
            tarjan(v);low[u]=min(low[u],low[v]);
        }
        else if(vis[v]) low[u]=min(low[u],dfn[v]);
    }
    if(low[u]==dfn[u])
    {
//      printf("______________________________________\n");
        int x;
        do
        {
            x=sta[top--];vis[x]=0;fa[x]=u;bar[u]|=bar[x];
//          printf("%d\n",x);
            if(x!=u) a[u]+=a[x];
        }while(x!=u);
    }
}
void spfa()
{
    queue<int> q;q.push(st); dis[st]=a[st];
    while(!q.empty())
    {
        int u=q.front(); q.pop();
        vis[u]=0;
        for(int j=head[u];j;j=e[j].nxt)
        {
            int v=e[j].v;
            if(dis[v]<dis[u]+a[v])
            {
                dis[v]=dis[u]+a[v];
                if(!vis[v]) vis[v]=1,q.push(v);
            }
        }
    }
}
int main()
{
    scanf("%d%d",&n,&m);
    for(int i=1,u,v;i<=m;i++)
        scanf("%d%d",&u,&v),add(u,v);
    for(int i=1;i<=n;i++) scanf("%d",&a[i]),fa[i]=i;
    scanf("%d%d",&st,&o); tot=0;
    for(int i=1,x;i<=o;i++) scanf("%d",&x),bar[x]=1;
    tarjan(st); tot=0; memset(head,0,sizeof(head));
    for(int i=1;i<=m;i++)
    {
        int u=fa[e[i].u],v=fa[e[i].v];
        if(u==v) continue; add(u,v);
//      printf("%d %d\n",u,v);
    }
    spfa();
    for(int i=1;i<=n;i++) if(fa[i]==i&&bar[i]) maxn=max(maxn,dis[i]);
    printf("%d\n",maxn);
    return 0;
}