POJ 2607

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <algorithm>
 5 using namespace std;
 6 
 7 const int inf=9999999;
 8 const int MAXN=505;
 9 int maze[MAXN][MAXN];
10 bool house[MAXN];
11 int dis[MAXN],fire,n;
12 
13 int main(){
14     int u,v,w; 
15     while(scanf("%d%d",&fire,&n)!=EOF){
16         memset(house,false,sizeof(house));
17         for(int i=1;i<MAXN;i++){ 
18             maze[i][i]=0; dis[i]=inf;
19             for(int j=i+1;j<MAXN;j++)
20             maze[i][j]=maze[j][i]=inf;
21         }
22         int station;
23         for(int i=0;i<fire;i++){
24             scanf("%d",&station);
25             house[station]=true;
26             dis[station]=0;
27         }
28         while(~scanf("%d%d%d",&u,&v,&w)){
29             maze[u][v]=maze[v][u]=min(w,maze[u][v]);
30         }
31         for(int k=1;k<=n;k++){
32             for(int i=1;i<=n;i++){
33                 for(int j=1;j<=n;j++){
34                     if(maze[i][k]+maze[k][j]<maze[i][j]){
35                         maze[i][j]=maze[i][k]+maze[k][j];
36                     }
37                 }
38             }
39         }
40         for(int i=1;i<=n;i++){
41             for(int j=1;j<=n;j++){
42                 if(house[j])
43                 dis[i]=min(dis[i],maze[i][j]);
44             }
45         }
46     //    for(int i=1;i<=n;i++)
47     //    cout<<dis[i]<<endl;
48         int tmp,ans,s=inf;
49         for(int i=1;i<=n;i++){
50             tmp=0;
51             for(int j=1;j<=n;j++){
52                 tmp=max(min(dis[j],maze[i][j]),tmp);
53             }
54             if(tmp<s){
55                 s=tmp; ans=i; 
56             }
57         }
58         printf("%d\n",ans);
59     }
60     return 0;
61 }