POJ-1797 Heavy Transportation(最大生成树)

 1 #include <cstdio>
 2 #include <iostream>
 3 #include <algorithm>
 4 using namespace std;
 5 const int MAX=1005;
 6 int t;
 7 int n,m,cas;
 8 int fa[MAX];
 9 struct Edge{
10     int u,v;
11     int w;
12     bool operator < (const Edge &tt) const {
13         return w>tt.w;
14     }
15 }edge[MAX*MAX];
16 int getfather(int x){
17     if (fa[x]==x) return x;
18     return fa[x]=getfather(fa[x]);
19 }
20 inline int read(){
21     int an=0,x=1;char c=getchar();
22     while (c<‘0‘ || c>‘9‘) {if (x==‘-‘) x=-1;c=getchar();}
23     while (c>=‘0‘ && c<=‘9‘) {an=an*10+c-‘0‘;c=getchar();}
24     return an*x;
25 }
26 int main(){
27     freopen ("heavy.in","r",stdin);
28     freopen ("heavy.out","w",stdout);
29     int i,j,an;
30     t=read();
31     while (t--){
32     n=read(),m=read();an=1000000005;
33     for (i=1;i<=m;i++){
34         edge[i].u=read();
35         edge[i].v=read();
36         edge[i].w=read();
37     }
38     sort(edge+1,edge+m+1);
39     for (i=1;i<=n;i++) fa[i]=i;
40     for (i=1;i<=m;i++){
41         int dx=getfather(edge[i].u);
42         int dy=getfather(edge[i].v);
43         if (getfather(1)!=getfather(n)){
44             an=edge[i].w;
45             fa[dx]=dy;
46         }
47         else break;
48     }
49     printf("Scenario #%d:\n%d\n\n",++cas,an);
50     }
51     return 0;
52 }