Luogu P2446 [SDOI2010]大陆争霸 题解

#include<bits/stdc++.h>
using namespace std;
inline int read(){
int res=0,f=1;char ch=getchar();
while(!isdigit(ch)) f=ch=='-'?-1:f,ch=getchar();
while(isdigit(ch)) res=(res<<3)+(res<<1)+(ch&15),ch=getchar();
return res*f; 
}
inline void write(int x){
if(x<0) putchar('-'),x=-x;
if(x<10) putchar(x+'0');
else write(x/10),putchar(x%10+'0');
}
int n,m,in[3010],fir[3010],nxt[70010],son[70010],w[70010],tot,vis[3010],t[3010],g[3010],d[3010];
vector<int> v[3010];
inline void add(int x,int y,int z){++tot;nxt[tot]=fir[x];fir[x]=tot;son[tot]=y;w[tot]=z;}
priority_queue<pair<int,int> > q;
inline void Dij(){
while(!q.empty()) q.pop();
memset(d,63,sizeof(d));
memset(t,63,sizeof(t));
in[1]=g[1]=t[1]=d[1]=0;
q.push(make_pair(0,1));
while(!q.empty()){
pair<int,int> u=q.top();q.pop();
if(vis[u.second]) continue ;
vis[u.second]=1;
for(int to,i=fir[u.second];i;i=nxt[i]){
to=son[i];
if(t[to]>d[u.second]+w[i]){
t[to]=d[u.second]+w[i];
if(!in[to]){
d[to]=max(g[to],t[to]);
q.push(make_pair(-d[to],to));
}
}
}
for(auto i:v[u.second]){
g[i]=max(g[i],d[u.second]);
in[i]--;
if(!in[i]){
d[i]=max(g[i],t[i]);
q.push(make_pair(-d[i],i));
}
}
}
}
int main(){
n=read(),m=read();
for(int x,y,z,i=1;i<=m;i++) x=read(),y=read(),z=read(),add(x,y,z);
for(int x,i=1;i<=n;i++){
x=read(),in[i]=x;
for(int y,j=1;j<=x;j++) y=read(),v[y].push_back(i);
}
Dij();
return write(d[n]),0;
}