思路：

先 Tarjan 缩点，然后再用拓扑上 DP 求出最长路。最后找出所酒馆所在的 SCC 并更新答案。

代码：

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define MAXN 500001

int n, m, s, p, u, v, cnt, ssum, ans;
int a[MAXN], f[MAXN], us[MAXN], vs[MAXN], in[MAXN];
int dfn[MAXN], low[MAXN], scc[MAXN], sum[MAXN];
vector<int> vec;
vector<int> e[MAXN], g[MAXN];
bitset<MAXN> vis;
stack<int> st;
queue<int> que;

void tarjan(int x){
	dfn[x] = low[x] = ++cnt;
	vis.set(x);
	st.push(x);
	for (auto i: e[x]){
		if (!dfn[i]){
			tarjan(i);
			low[x] = min(low[x], low[i]);
		}else if (vis.test(i)) low[x] = min(low[x], dfn[i]);
	}
	
	if (dfn[x] == low[x]){
		scc[x] = ++ssum;
		sum[ssum] = a[x];
		while (st.top() != x){
			scc[st.top()] = ssum;
			sum[ssum] += a[st.top()];
			vis.reset(st.top());
			st.pop();
		}
		st.pop();
		vis.reset(x);
	}
}

void topsort(){
	que.push(scc[s]);
	f[scc[s]] = sum[scc[s]];
	while (!que.empty()){
		u = que.front();
		que.pop();
		
		for (auto i: g[u]){
			f[i] = max(f[i], f[u]+sum[i]);
			if (!(--in[i])) que.push(i);
		}
	}
}

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    
    cin >> n >> m;
    for (int i(1); i<=m; ++i){
    	cin >> us[i] >> vs[i];
    	e[us[i]].push_back(vs[i]);
	}
	for (int i(1); i<=n; ++i) cin >> a[i];
	cin >> s >> p;
	while (p--){
		cin >> u;
		vec.push_back(u);
	}
	tarjan(s);
	
	for (int i(1); i<=m; ++i){
		u = scc[us[i]];
		v = scc[vs[i]];
		if (u != v){
			g[u].push_back(v);
			++in[v];
		}
	}
	
	topsort();
	for (int i: vec) ans = max(ans, f[scc[i]]);
	cout << ans;

    return 0;
}