prim模板 

int vis[30];
int n;
int map[30][30];
int d[30];
int prim(){  
    int i,j,mi,v;  
    for(i=0;i<n;i++){  
        d[i]=map[0][i];  
        vis[i]=0;  
    }  
    for(i=1;i<=n;i++){  
        mi=1<<30;  
        for(j=0;j<n;j++){  
            if(!vis[j] && mi>d[j]){  
                v=j;  
                mi=d[j];  
            }  
        }  
        vis[v]=1;  
        for(j=0;j<n;j++)  
            if(!vis[j] && d[j]>map[v][j])
                d[j]=map[v][j];  
    }  
    for(i=1;i<n;i++) d[0]+=d[i];  
    return d[0];  
}

 

heap优化

http://www.nocow.cn/index.php/Prim%E7%AE%97%E6%B3%95

 1 /*
 2 二叉堆优化Prim算法
 3 Author:YangZX
 4 Date：9.11 2011 
 5 */
 6 #include <iostream>
 7 using namespace std;
 8 const int MAXV = 10001, MAXE = 100001, INF = (~0u)>>2;
 9 struct edge{
10     int t, w, next;
11 }es[MAXE * 2];
12 int h[MAXV], cnt, n, m, heap[MAXV], size, pos[MAXV], dist[MAXV];
13 void addedge(int x, int y, int z)
14 {
15     es[++cnt].t = y;
16     es[cnt].next = h[x];
17     es[cnt].w = z;
18     h[x] = cnt;
19 }
20  
21 void heapup(int k)
22 {
23     while(k > 1){
24         if(dist[heap[k>>1]] > dist[heap[k]]){    
25             swap(pos[heap[k>>1]], pos[heap[k]]);
26             swap(heap[k>>1], heap[k]);
27             k>>=1;
28         }else
29             break;
30     }
31 }
32 void heapdown(int k)
33 {
34     while((k<<1) <= size){
35         int j;
36         if((k<<1) == size || dist[heap[(k<<1)]] < dist[heap[(k<<1)+1]])
37             j = (k<<1);
38         else
39             j = (k<<1) + 1;
40         if(dist[heap[k]] > dist[heap[j]]){
41             swap(pos[heap[k]], pos[heap[j]]);
42             swap(heap[k], heap[j]);
43             k=j;
44         }else
45             break;
46     }
47 }
48 void push(int v, int d)
49 {
50     dist[v] = d;
51     heap[++size] = v;
52     pos[v] = size;
53     heapup(size);
54 }
55 int pop()
56 {
57     int ret = heap[1];
58     swap(pos[heap[size]], pos[heap[1]]);
59     swap(heap[size], heap[1]);
60     size--;
61     heapdown(1);
62     return ret;
63 }
64  
65 int prim()
66 {
67     int mst = 0, i, p;
68     push(1, 0);
69     for(i=2; i<=n; i++)
70         push(i, INF);
71     for(i=1; i<=n; i++){
72         int t = pop();
73         mst += dist[t];
74         pos[t] = -1;
75         for(p = h[t]; p; p = es[p].next){
76             int dst = es[p].t;
77             if(pos[dst] != -1 && dist[dst] > es[p].w){
78                 dist[dst] = es[p].w;
79                 heapup(pos[dst]);
80                 heapdown(pos[dst]);
81             }
82         }
83     }
84     return mst;
85 }
86 int main()
87 {
88     cin>>n>>m;
89     for(int i=1; i<=m; i++){
90         int x, y, z;
91         cin>>x>>y>>z;
92         addedge(x, y, z);
93         addedge(y, x, z);
94     }
95     cout<<prim()<<endl;
96     return 0;
97 }

 

posted @ 2015-01-26 19:27  verlen  阅读(727)  评论(0)  编辑  收藏  举报