[Apio2009]Atm

#include<cstdio>
#include<cstring>
#include<iostream>
#include<string>
#include<vector>
#include<queue>
#include<stack>
#include<set>
#include<algorithm>
using namespace std;
#define N 500001
stack<int>Sta;
queue<int>Que;
struct edge
{
    int u,v,next;
}edge1[N],edge2[N];
bool isBar[N],inStack[N];
int low[N],dfn[N],belong[N],money[N],newMoney[N],cnt,Time,start;
int maxMoney[N],head[N],head2[N];
 
void add(int u, int v, int id)
{
    edge1[id].u = u;
    edge1[id].v = v;
    edge1[id].next = head[u];
    head[u] = id;
}
 
void add2(int u, int v, int id)
{
    edge2[id].u = u;
    edge2[id].v = v;
    edge2[id].next = head2[u];
    head2[u] = id;
}
void Tarjan(int s)
{
    dfn[s] = low[s] = ++Time;
    Sta.push(s);
    inStack[s] = true;
    for(int u = head[s]; ~u; u = edge1[u].next)
    {
        int v = edge1[u].v;
        if(dfn[v] == 0){
            Tarjan(v);
            low[s] = min(low[s], low[v]);
        }
        else if(inStack[v] == true){
            low[s] = min(low[s], dfn[v]);
        }
    }
    if(dfn[s] == low[s])
        {
            cnt ++;
            while(!Sta.empty()){
              int temp = Sta.top(); Sta.pop();
              belong[temp] = cnt;
              newMoney[cnt] += money[temp];
              inStack[temp] = false;
              if(temp == s) break;
            }
        }
}
 
int spfa()
{
    int ans = 0;
    Que.push(start);
    memset(maxMoney,0,sizeof(maxMoney));
    maxMoney[start] = newMoney[start];
    while(!Que.empty())
    {
        int now = Que.front(); Que.pop();
        for(int u = head2[now]; ~u; u = edge2[u].next)
        {
            int v = edge2[u].v;
            if(maxMoney[now] + newMoney[v] > maxMoney[v])
            {
                maxMoney[v] = maxMoney[now] + newMoney[v];
                Que.push(v);
            }
            if(isBar[v]) ans = max(ans, maxMoney[v]);
        }
    }
    return ans;
}
 
int main()
{
    int n,m,a,b,s,p;
    scanf("%d%d",&n,&m);
    memset(head,-1,sizeof(head));
    for (int i = 0; i < m; i++) {
      /* code */
      scanf("%d%d",&a, &b);
      add(a,b,i+1);
    }
    for (int i = 1; i <= n; i++) {
      /* code */
      scanf("%d",&money[i]);
    }
    scanf("%d%d",&s,&p);
    memset(inStack,false,sizeof(inStack));
    memset(newMoney,0,sizeof(newMoney));
    memset(isBar,false,sizeof(isBar));
    memset(dfn,0,sizeof(dfn));
    cnt = Time = 0;
    for(int i = 1; i <= n; i++) if(dfn[i] == 0) Tarjan(i);
    if(cnt == 1) {printf("%d",newMoney[cnt]);return 0;}
    for(int i=0;i<p;i++)
    {
      scanf("%d", &a);
      isBar[belong[a]] = true;
    }
    start = belong[s];
    memset(head2,-1,sizeof(head2));
    int kkk = 0;
    for(int i =1; i <= n; i ++)
    {
        for(int u = head[i]; ~u; u = edge1[u].next){
            int v = edge1[u].v;
            if(belong[i] != belong[v]){
                add2(belong[i],belong[v],++kkk);
            }
        }
    }
 
    int ans = spfa();
    printf("%d", ans);
}