基础最短路（模板 spfa）

 1 # include<iostream>
 2 # include<cstdio>
 3 # include<cstring>
 4 # include<queue>
 5 # include<algorithm>
 6 using namespace std;
 7 const int INF=1<<30;
 8 struct edge
 9 {
10     int to,w,nxt;
11 };
12 edge e[2005];
13 int head[1005],dis[1005];
14 int t,s,d,cnt,sta[1005],ed[1005];
15 void add(int a,int b,int c)
16 {
17     e[cnt].to=b;
18     e[cnt].w=c;
19     e[cnt].nxt=head[a];
20     head[a]=cnt++;
21 }
22 int spfa(int from,int to)
23 {
24     fill(dis,dis+1004,INF);
25     dis[from]=0;
26     queue<int>q;
27     q.push(from);
28     while(!q.empty()){
29         int u=q.front();
30         q.pop();
31         for(int i=head[u];i!=-1;i=e[i].nxt){
32             if(dis[e[i].to]>dis[u]+e[i].w){
33                 dis[e[i].to]=dis[u]+e[i].w;
34                 q.push(e[i].to);
35             }
36         }
37     }
38     return dis[to];
39 }
40 int main()
41 {
42     int i,j,a,b,c;
43     while(scanf("%d%d%d",&t,&s,&d)!=EOF)
44     {
45         cnt=0;
46         memset(head,-1,sizeof(head));
47         for(i=1;i<=t;++i){
48             scanf("%d%d%d",&a,&b,&c);
49             add(a,b,c);
50             add(b,a,c);
51         }
52         for(i=0;i<s;++i)
53             scanf("%d",&sta[i]);
54         for(i=0;i<d;++i)
55             scanf("%d",&ed[i]);
56         int ans=INF;
57         for(i=0;i<s;++i)
58             for(j=0;j<d;++j)
59                 ans=min(ans,spfa(sta[i],ed[j]));
60         printf("%d\n",ans);
61     }
62     return 0;
63 }