Need to construct two graphs, one is the original graph, and the other is a minimized graph with only the hotel and the starting and ending points.
Use SPFA as usual, but stupidly get TLE multiple times.
//============================================================================
// Name : Hotel booking.cpp
// Date : 2013/5/12 下午7:02:55
// Author : GCA
//============================================================================
#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <climits>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <cctype>
#include <utility>
using namespace std;
#ifdef ONLINE\_JUDGE
#define ll "%lld"
#else
#define ll "%I64d"
#endif
typedef unsigned int uint;
typedef long long int Int;
#define Set(a,s) memset(a,s,sizeof(a))
#define Write(w) freopen(w,"w",stdout)
#define Read(r) freopen(r,"r",stdin)
#define Pln() printf("\\n")
#define I\_de(x,n)for(int i=0;i<n;i++)printf("%d ",x\[i\]);Pln()
#define De(x)printf(#x"%d\\n",x)
#define For(i,x)for(int i=0;i<x;i++)
#define CON(x,y) x##y
#define Pmz(dp,nx,ny)for(int hty=0;hty<ny;hty++){for(int htx=0;htx<nx;htx++){\\
printf("%d ",dp\[htx\]\[hty\]);}Pln();}
#define M 10003
#define PII pair<int,int\>
#define PB push\_back
#define oo (1<<29)
#define Set\_oo 0x3f
#define Is\_debug true
#define debug(...) if(Is\_debug)printf("DEBUG: "),printf(\_\_VA\_ARGS\_\_)
#define FOR(it,c) for(\_\_typeof((c).begin()) it=(c).begin();it!=(c).end();it++)
#define eps 1e-6
bool xdy(double x,double y){return x>y+eps;}
bool xddy(double x,double y){return x>y-eps;}
bool xcy(double x,double y){return x<y-eps;}
bool xcdy(double x,double y){return x<y+eps;}
int min3(int x,int y,int z){
int tmp=min(x,y);
return min(tmp,z);
}
int max3(int x,int y,int z){
int tmp=max(x,y);
return max(tmp,z);
}
struct node{
int to,w;
node(int x,int y):to(x),w(y){};
};
vector<node> mz\[M\],mz2\[M\];
int n,m;
int end1\[110\];
int vis\[M\];
int dis\[M\];
int end1n;
void spfa(int src){
queue<int\> q;
for(int i=0;i<=n;i++){
dis\[i\]=oo;
vis\[i\]=0;
}
dis\[src\]=0;
vis\[src\]=1;
q.push(src);
while(!q.empty()){
int u=q.front();
int nowd=dis\[u\];
q.pop();
FOR(it,mz\[u\]){
int v=(\*it).to;
int w=(\*it).w;
if(nowd+w<dis\[v\]){
dis\[v\]=nowd+w;
if(!vis\[v\]){
q.push(v);
vis\[v\]=1;
}
}
}
vis\[u\]=0;
}
}
int spfa2(int src,int end){
queue<int\> q;
for(int i=0;i<=n;i++){
dis\[i\]=oo;
vis\[i\]=0;
}
dis\[src\]=0;
vis\[src\]=1;
q.push(src);
while(!q.empty()){
int u=q.front();
int nowd=dis\[u\];
q.pop();
FOR(it,mz2\[u\]){
int v=(\*it).to;
int w=(\*it).w;
if(nowd+w<dis\[v\]){
dis\[v\]=nowd+1;
if(!vis\[v\]){
q.push(v);
vis\[v\]=1;
}
}
}
vis\[u\]=0;
}
return dis\[end\];
}
void solve(){
// debug("-1");
for(int i=0;i<end1n;i++){
spfa(end1\[i\]);
for(int j=i+1;j<end1n;j++){
if(dis\[end1\[j\]\]<=600){
mz2\[end1\[i\]\].PB(node(end1\[j\],dis\[end1\[j\]\]));
mz2\[end1\[j\]\].PB(node(end1\[i\],dis\[end1\[j\]\]));
}
}
}
int tmp;
if((tmp=spfa2(1,n))==oo)printf("-1\\n");
else printf("%d\\n",tmp-1);
}
int main() {
ios\_base::sync\_with\_stdio(0);
while(~scanf("%d",&n)&&n){
scanf("%d",&end1n);
for(int i=0;i<end1n;i++){
scanf("%d",&end1\[i\]);
}
end1\[end1n++\]=1;
end1\[end1n++\]=n;
scanf("%d",&m);
for(int i=0;i<m;i++){
int u,v,w;
scanf("%d%d%d",&u,&v,&w);
mz\[u\].PB(node(v,w));
mz\[v\].PB(node(u,w));
}
solve();
for(int i=0;i<=n;i++){
mz\[i\].clear();
mz2\[i\].clear();
}
}
}