luoguP3366 [模板] 最小生成树

 1 #include<bits/stdc++.h>
 2 #define R register int
 3 using namespace std;
 4 
 5 typedef pair<int,int> PII;
 6 struct node{
 7     int v,w,next;
 8 }a[400005];                //表结点
 9 
10 int n,m,k,cnt,sum,x,y,z;
11 int head[5005],len[5005],vis[5005];
12 priority_queue<PII,vector<PII>,greater<PII> > pq;
13 
14 void add(int u,int v,int w){
15     a[++k].v=v;
16     a[k].w=w;
17     a[k].next=head[u];
18     head[u]=k;
19 }
20 
21 void prim(){
22     len[1]=0;
23     pq.push(make_pair(0,1));
24     while(!pq.empty()&&cnt<n){
25         int l=pq.top().first,m=pq.top().second;
26         pq.pop();
27         if(!vis[m]){
28             cnt++;
29             vis[m]=1;
30             sum+=l;
31             for(R i=head[m];i!=-1;i=a[i].next){
32                 if(!vis[a[i].v]&&a[i].w<len[a[i].v])
33                     len[a[i].v]=a[i].w,pq.push(make_pair(a[i].w,a[i].v));
34             }
35         }
36     }
37 }
38 
39 int main(){
40     memset(head,-1,sizeof(head));
41     memset(len,0x3f,sizeof(len));
42     scanf("%d%d",&n,&m);
43     while(m--){
44         scanf("%d%d%d",&x,&y,&z);
45         add(x,y,z);
46         add(y,x,z);
47     }
48     prim();
49     if(cnt==n)
50         printf("%d\n",sum);
51     else
52         printf("orz\n");
53     return 0;
54 }