POJ2485 Highways

 1 /*by SilverN*/
 2 #include<algorithm>
 3 #include<iostream>
 4 #include<cstring>
 5 #include<cstdio>
 6 #include<cmath>
 7 using namespace std;
 8 const int mxn=510;
 9 int n,m;
10 int mp[mxn][mxn];
11 int dis[mxn];
12 bool vis[mxn];
13 int ans=0;
14 int main(){
15     int i,j;
16     int T;
17     scanf("%d",&T);
18     while(T--){
19         scanf("%d",&n);
20         ans=0;
21         memset(mp,0x2f,sizeof mp);
22         memset(dis,0x2f,sizeof dis);
23         memset(vis,0,sizeof vis);
24         int u,v,d;
25         for(i=1;i<=n;i++)
26          for(j=1;j<=n;j++){
27              scanf("%d",&m);
28              mp[i][j]=m;
29              if(!m)mp[i][j]=1e6;
30          }
31         dis[1]=0;
32         int pos,mini;
33         while(1){
34             pos=0;mini=0x2f2f2f2f;
35             for(i=1;i<=n;i++){
36                 if(!vis[i] && dis[i]<mini){
37                     mini=dis[i];
38                     pos=i;
39                 }
40             }
41             if(pos==0)break;
42             ans=max(ans,dis[pos]);dis[pos]=0;vis[pos]=1;
43             for(i=1;i<=n;i++){
44                 dis[i]=min(dis[i],mp[pos][i]);
45             }
46         }
47         printf("%d\n",ans);
48     }
49     return 0;
50 }