ZOJ 3794 Greedy Driver spfa

#include<stdio.h>
#include<string.h>
#include<iostream>
#include<math.h>
#include<algorithm>
#include<queue>
#include<vector>
using namespace std;
#define N 10050
#define M 200010
#define inf 1000000
#define ll long long
struct Edge{
	int from, to, dis, nex;
}edge[M], e[M];
int head[N],edgenum;
void add(int u,int v,int d){
	Edge E={u,v,d,head[u]};
	edge[edgenum] = E;
	head[u] = edgenum++;
}
int H[N], edg;
void add2(int u,int v,int d){
	Edge E={u,v,d,H[u]};
	e[edg] = E;
	H[u] = edg++;
}
int n, m, k;
int F[N], T[N];//F是车站 T是贩卖点
int f[N];//起点到这里最多能剩多少油
bool inq[N];
void spfa(){
	queue<int>q;
	memset(f,-1,sizeof f);
	memset(inq, 0, sizeof inq);
	f[1] = k; q.push(1);
	while(!q.empty()){
		int u = q.front(); q.pop(); inq[u] = 0;
		for(int i = head[u]; ~i; i = edge[i].nex){
			int v = edge[i].to;
			if(f[v]< f[u] - edge[i].dis){
				if(F[v])f[v]=k;
				else
				f[v] = f[u] - edge[i].dis;
				if(!inq[v])inq[v] = 1, q.push(v);
			}
		}
	}
}
int dis[N];//把边反一下跑出距离终点的最短路，也就是从这个点到终点最少要多少油
void bfs(){
	for(int i = 1; i <= n; i++)dis[i] = inf;
	memset(inq, 0, sizeof inq);
	dis[n] = 0;
	queue<int>q; q.push(n);
	while(!q.empty()){
		int u = q.front(); q.pop(); inq[u] = 0;
		for(int i = H[u]; ~i ; i = e[i].nex){
			int v = e[i].to;
			
			if(dis[v]>dis[u]+e[i].dis){
				if(F[v])dis[v] = 0; //由于v是加油站，所以到这点剩下0的油量也没事，自然会补满的
				else
				dis[v] = dis[u]+e[i].dis;
				if(!inq[v])inq[v] = 1, q.push(v);
			}
		}
	}
}
void init(){memset(head, -1, sizeof head);edgenum = 0;memset(H, -1, sizeof H);edg = 0;}
int main(){
	int i,u,v,d;
	while(~scanf("%d %d %d",&n,&m,&k)){
		init();
		memset(F, 0, sizeof F);
		memset(T, 0, sizeof T);
		while(m--){
			scanf("%d %d %d",&u,&v,&d);
			add(u,v,d);
			add2(v,u,d);
		}
		scanf("%d",&m);		while(m--){scanf("%d",&u);F[u]=1;}
		scanf("%d",&m);		while(m--){scanf("%d %d",&u,&v);T[u]=v;}
		spfa();
		if(f[n]==-1){puts("-1");continue;}
		bfs();
		int ans = 0;
		for(int i = 1; i <= n; i++)if(T[i] && f[i]!=-1&&dis[i]<inf)
			ans = max(ans, (f[i] - dis[i])*T[i]);
		cout<<ans<<endl;
	}
	return 0;
}
/*
2 1 1
1 2 2
1
1
0


*/