bzoj1179 [Apio2009]Atm

#include<bits/stdc++.h>
#define N 600000
using namespace std;
int n,m,A[N+1],x,y,s,p;
int first[N+1],nxt[N+1],to[N+1],siz;
int first2[N+1],nxt2[N+1],to2[N+1],siz2;
int low[N+1],dfn[N+1],id;
int fc[N+1],vis[N+1];
int sta[10*N+1],top,num[N+1];
int dis[N+1];
int belong[N+1],cnt,E[N+1],ans;
int f[N+1];
inline char nc()
{
static char buf[100000],*p1=buf,*p2=buf;
return p1==p2&&(p2=(p1=buf)+fread(buf,1,100000,stdin),p1==p2)?EOF:*p1++;
}
inline int read()
{
int x=0,b=1;
char c=nc();
for(;!(c<='9'&&c>='0');c=nc())if(c=='-')b=-1;
for(;c<='9'&&c>='0';c=nc())x=x*10+c-'0';
return x*b;
}
inline void write(int x)
{
if(x==0)putchar('0');
else
{
char buf[15];
int len=0;
if(x<0)putchar('-'),x=-x;
while(x)buf[++len]=x%10+'0',x/=10;
for(int i=len;i>=1;i--)putchar(buf[i]);
}
putchar(' ');
}
inline void add(int x,int y)
{
nxt[siz]=first[x];
first[x]=siz;
to[siz]=y;
siz++;
}
inline void add2(int x,int y)
{
nxt2[siz2]=first2[x];
first2[x]=siz2;
to2[siz2]=y;
siz2++;
}
inline void tarjan(int x)
{
dfn[x]=low[x]=++id;
sta[++top]=x,vis[x]=true;
for(int i=first[x];i!=-1;i=nxt[i])
{
int u=to[i];
if(!dfn[u])
tarjan(u),low[x]=min(low[x],low[u]);
else if(vis[u])low[x]=min(low[x],dfn[u]);
}
if(low[x]==dfn[x])
{
cnt++;int tmp;
do
{
tmp=sta[top--];
vis[tmp]=false;
belong[tmp]=cnt;
num[cnt]+=A[tmp];
if(fc[tmp])f[cnt]=true;
}while(tmp!=x);
}
}
inline void rebuild()
{
siz2=0,memset(first2,-1,sizeof(first2));
for(int i=1;i<=n;i++)
{
for(int j=first[i];j!=-1;j=nxt[j])
{
int u=to[j];
if(belong[i]==belong[u])continue;
add2(belong[i],belong[u]);
}
}
}
inline void SPFA(int s)
{
queue <int> Q;
Q.push(s);dis[s]=num[s];
E[s]=true;
while(!Q.empty())
{
int x=Q.front();Q.pop();
E[x]=false;
for(int i=first2[x];i!=-1;i=nxt2[i])
{
int u=to2[i];
if(dis[u]<dis[x]+num[u])
{
dis[u]=dis[x]+num[u];
if(E[u])continue;
Q.push(u),E[u]=true;
}
}
}
}
int main()
{
freopen("in.txt","r",stdin);
memset(first,-1,sizeof(first));
n=read();m=read();
for(int i=1;i<=m;i++)x=read(),y=read(),add(x,y);
for(int i=1;i<=n;i++)A[i]=read();
s=read(),p=read();
for(int i=1;i<=p;i++)x=read(),fc[x]=true;
for(int i=1;i<=n;i++)if(!dfn[i])tarjan(i);
rebuild();
SPFA(belong[s]);
for(int i=1;i<=cnt;i++)if(f[i])ans=max(ans,dis[i]);
cout<<ans;
return 0;
}