POJ 1679 The Unique MST

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cstdlib>
 5 #include <vector>
 6 #include <climits>
 7 #include <algorithm>
 8 #include <cmath>
 9 #define LL long long
10 #define INF 0x3f3f3f
11 using namespace std;
12 int mp[101][101],d[101];
13 int n,m;
14 bool vis[101];
15 int prim(){
16     int i,j,k,temp,index,ans = 0;
17     for(i = 1; i <= n; i++) d[i] = INF;
18     d[1] = 0;
19     memset(vis,false,sizeof(vis));
20     for(i = 0; i < n; i++){
21         temp = INF;
22         for(j = 1; j <= n; j++)
23             if(!vis[j] && d[j] < temp) temp = d[index = j];
24         k = 0;
25         for(j = 1; j <= n; j++){
26             if(vis[j] && mp[index][j] == temp) k++;
27         }
28         if(k > 1) return -1;
29         vis[index] = true;
30         ans += temp;
31         for(j = 1; j <= n; j++){
32             if(!vis[j] && d[j] > mp[index][j]) d[j] = mp[index][j];
33         }
34     }
35     return ans;
36 }
37 int main(){
38     int ks,i,j,u,v,w;
39     scanf("%d",&ks);
40     while(ks--){
41         scanf("%d%d",&n,&m);
42         for(i = 0; i <= n; i++)
43             for(j = 0; j <= n; j++)
44             mp[i][j] = INF;
45         for(i = 0; i < m; i++){
46             scanf("%d%d%d",&u,&v,&w);
47             if(mp[u][v] > w){
48                 mp[u][v] = mp[v][u] = w;
49             }
50         }
51         w = prim();
52         if(w < 0) puts("Not Unique!");
53         else printf("%d\n",w);
54     }
55     return 0;
56 }