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http://acm.fjut.edu.cn/Problem.jsp?pid=1545

FJUTOJ 1545

Prim

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 #include <iostream>
 5
 6 using namespace std;
 7 #define M 105
 8
 9 const int INF=1<<29;
10
11 int n,m,arr[M][M];
12
13 int prim()
14 {
15     int dis[M],vis[M],i,j,u,ans=0;
16     for(i=1;i<=n;i++)
17         dis[i]=arr[1][i],vis[i]=0;
18     vis[1]=1;
19     for(i=1;i<n;i++)
20     {
21         int mi=INF;
22         for(j=1;j<=n;j++)
23         {
24             if(!vis[j]&&dis[j]<mi)
25             {
26                 mi=dis[j];
27                 u=j;
28             }
29         }
30         vis[u]=1;
31         ans+=dis[u];
32         for(j=1;j<=n;j++)
33         {
34             if(!vis[j]&&arr[u][j]<dis[j])
35             {
36                 dis[j]=arr[u][j];
37             }
38         }
39     }
40     return ans;
41 }
42
43 int main()
44 {
45     int i,j,a,b,c;
46     while(scanf("%d",&n)&&n)
47     {
48         for(i=1;i<=n;i++)
49         {
50             for(j=1;j<=n;j++)
51             {
52                 arr[i][j]=INF;
53             }
54         }
55         scanf("%d",&m);
56         while(m--)
57         {
58             scanf("%d%d%d",&a,&b,&c);
59             arr[a][b]=arr[b][a]=min(arr[a][b],c);
60         }
61         printf("%d\n",prim());
62
63     }
64     return 0;
65 }

kruskal

 1 #include<cstdio>
 2 #include<algorithm>
 3 using namespace std;
 4 struct edge
 5 {
 6     int from,to,cost;
 7 }arr[105*105];
 8 int n,m,pre[105];
 9 void init()
10 {
11     for(int i=1;i<=n;i++)
12     {
13         pre[i]=i;
14     }
15 }
16 int findx(int x)
17 {
18     if(pre[x]==x)return x;
19     else return pre[x]=findx(pre[x]);
20 }
21 void join(int x,int y)
22 {
23     int fx=findx(x),fy=findx(y);
24     if(fx==fy)return;
25     pre[fy]=fx;
26 }
27 bool same(int x,int y)
28 {
29     return findx(x)==findx(y);
30 }
31 bool cmp(edge a,edge b)
32 {
33     return a.cost<b.cost;
34 }
35 int kruskal()
36 {
37     int ans=0;
38     sort(arr+1,arr+1+m,cmp);
39     for(int i=1;i<=m;i++)
40     {
41         if(same(arr[i].from,arr[i].to))
42         {
43             continue;
44         }
45         join(arr[i].from,arr[i].to);
46         ans+=arr[i].cost;
47     }
48     return ans;
49 }
50 int main()
51 {
52     while(scanf("%d",&n)&&n)
53     {
54         scanf("%d",&m);
55         init();
56         for(int i=1;i<=m;i++)
57         {
58             scanf("%d%d%d",&arr[i].from,&arr[i].to,&arr[i].cost);
59         }
60         printf("%d\n",kruskal());
61     }
62 }