【POJ】1287 Networking

 1 #include<iostream>
 2 #include<cstring>
 3 #include<cstdio>
 4 using namespace std;
 5 const int maxn = 55;
 6 const int inf = 0x3f3f3f3f;
 7 int mp[maxn][maxn];
 8 int dis[maxn];
 9 bool vis[maxn];
10 int n,m;
11 int prim(){
12     memset(dis,0x3f,sizeof(dis));
13     memset(vis,0,sizeof(vis)); 
14     int ans = 0;
15     dis[1] = 0;
16     while(1){
17         int k = 0;
18         for(int j = 1; j <= n;j++){
19             if(!vis[j] && dis[j] < dis[k])
20                 k = j; 
21         } 
22         if(!k) break;
23         vis[k] = 1; 
24         ans += dis[k];
25         for(int j = 1; j <= n;j++){
26             if(dis[j] > mp[k][j]){
27                 dis[j] = mp[k][j];
28             }
29 
30         }
31     }
32     return ans;
33 }
34 
35 
36 int main(){
37     while(cin>>n && n){
38         memset(mp,0x3f,sizeof(mp)); 
39         cin>>m;
40         if(m == 0){
41             cout<<0<<endl;
42             continue;
43         }
44         while(m--){
45             int x,y,w;
46             cin>>x>>y>>w;
47             mp[x][y] = mp[y][x] = min(mp[x][y],w);
48         }
49         cout<<prim()<<endl;
50     }
51 
52     return 0;
53 }