1 #include<cstdio> 2 #include<queue> 3 #include<algorithm> 4 #include<vector> 5 #include<cstring> 6 using namespace std; 7 int cmp[500001],sum,n,m,Us[500001],Vs[500001],t,w[500001],sta,k,ans,dis[500001]; 8 bool vis[500001],inq[500001]; 9 struct Edge{int v,w;Edge(const int &a,const int &b){v=a;w=b;}Edge(){}};10 vector<int>G[500001],rG[500001],G2[500001],vs;11 typedef vector<int>::iterator ITER;12 queue<int>q;13 void dfs(int U)14 {15     vis[U]=1;16     for(ITER it=G[U].begin();it!=G[U].end();++it) if(!vis[*it]) dfs(*it);17     vs.push_back(U);18 }19 void dfs2(int U)20 {21     cmp[U]=sum;22     for(ITER it=rG[U].begin();it!=rG[U].end();++it) if(!cmp[*it]) dfs2(*it);23 }24 void scc()25 {26     for(int i=1;i<=n;i++) if(!vis[i]) dfs(i);27     ITER it=vs.end(); --it;28     for(;;it--)29       {30         if(!cmp[*it]) {++sum; dfs2(*it);}31         if(it==vs.begin()) break;32       }33 }34 void spfa(const int &s)35 {36     dis[s]=w[s]; q.push(s); inq[s]=1;37     while(!q.empty())38       {39         int U=q.front();40         for(ITER it=G2[U].begin();it!=G2[U].end();it++)41           if(dis[*it]<dis[U]+w[*it])42             {43               dis[*it]=dis[U]+w[*it];44               if(!inq[*it])45                 {46                   q.push(*it);47                   inq[*it]=1;48                 }49             }50         q.pop(); inq[U]=0;51       }52 }53 int main()54 {55     scanf("%d%d",&n,&m);56     for(int i=1;i<=m;++i)57       {58           scanf("%d%d",&Us[i],&Vs[i]);59           G[Us[i]].push_back(Vs[i]);60           rG[Vs[i]].push_back(Us[i]);61       } scc();62     for(int i=1;i<=n;++i) {scanf("%d",&t); w[cmp[i]]+=t;}63     for(int i=1;i<=m;++i)64       if(cmp[Us[i]]!=cmp[Vs[i]])65         G2[cmp[Us[i]]].push_back(cmp[Vs[i]]);66     scanf("%d%d",&sta,&k);67     spfa(cmp[sta]);68     for(int i=1;i<=k;++i)69       {70           scanf("%d",&t);71           ans=max(dis[cmp[t]],ans);72       } printf("%d\n",ans);73     return 0;74 }