07:清泉-改（prime+堆）

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 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<algorithm>
 5 #include<queue>
 6 using namespace std;
 7 const int MAXN=1200001;
 8 const int maxn=0x3f;
 9 void read(int &n)
10 {
11     char c='+';int x=0;bool flag=0;
12     while(c<'0'||c>'9'){c=getchar();if(c=='-')flag=1;}
13     while(c>='0'&&c<='9')
14     x=(x<<1)+(x<<3)+c-48,c=getchar();
15     flag==1?n=-x:n=x;
16 }
17 struct node
18 {
19     int u,v,w,nxt;
20 }edge[MAXN];
21 int head[MAXN];
22 int num=1;
23 int add_edge(int x,int y,int z)
24 {
25     edge[num].u=x;
26     edge[num].v=y;
27     edge[num].w=z;
28     edge[num].nxt=head[x];
29     head[x]=num++;
30 }
31 int n,m;
32 int vis[MAXN];
33 int dis[MAXN];
34 struct pr
35 {
36     int p,v;
37     pr()
38     {p=v=0;}
39     pr(int a,int b)
40     {p=a;v=b;}
41     bool operator<(const pr&a)const 
42     {return v>a.v;}
43 }inc;
44 void prime()
45 {
46     //vis[1]=1;
47     priority_queue<pr>q;
48     memset(dis,maxn,sizeof(dis));
49     dis[1]=0;
50     q.push(pr(1,0));
51     int ans=0;
52 //    for(int i=head[1];i!=-1;i=edge[i].nxt)
53 //        q.push(pr(edge[i].v,edge[i].w));
54     
55     for(int k=1;k<=n;k++)
56     {
57         int pos;
58         while(vis[q.top().p]&&q.size()>=0)
59             q.pop();
60     
61         pos=q.top().p;
62         vis[pos]=1;
63         ans+=dis[pos];
64         for(int i=head[pos];i!=-1;i=edge[i].nxt)
65             if(vis[edge[i].v]==0&&dis[edge[i].v]>edge[i].w)
66             {
67                 dis[edge[i].v]=edge[i].w;
68                 q.push(pr(edge[i].v,edge[i].w));
69             }
70                 
71     }
72     printf("%d",ans);
73 }
74 int main()
75 {
76     read(n);read(m);
77     memset(head,-1,sizeof(head));
78     for(int i=1;i<=m;i++)
79     {
80         int x,y,z;
81         read(x);read(y);read(z);
82         add_edge(x,y,z);
83         add_edge(y,x,z);
84     }
85     prime();
86     return 0;
87 }