最小生成树

 1 #include<cstring>
 2 #include<cstdio>
 3 #include<vector>
 4 using namespace std;
 5 const int MAXN=10000;
 6 vector<int> W[MAXN],E[MAXN];
 7 int dis[MAXN],ans=0,n,m,map[MAXN][MAXN];
 8 bool vis[MAXN]={0};
 9 void add(int u,int v,int w1){
10     E[u].push_back(v);
11     W[u].push_back(w1);
12 }
13 
14 void prim(){
15     memset(dis,127,sizeof(dis));
16     dis[1]=0;
17     for (int i=0;i<n;i++){
18         int min=100000,minn;
19         for (int j=1;j<=n;j++){
20             if (dis[j]<min&&!vis[j]){
21                 min=dis[j];
22                 minn=j;
23             }
24         }
25         vis[minn]=1;
26         ans+=min;
27         for (int j=0;j<E[minn].size();j++){
28             if (W[minn][j]<dis[E[minn][j]]){
29                 dis[E[minn][j]]=W[minn][j];
30             }    
31         }
32     }
33 }
34 
35 int main(){
36     scanf("%d",&n);
37     int u,v,w1;
38     for (int i=1;i<=n;i++){
39         for (int j=1;j<=n;j++) scanf("%d",&map[i][j]);
40     }
41     for (int i=1;i<=n;i++)
42         for (int j=1;j<i;j++) {
43             add(j,i,map[i][j]);
44             add(i,j,map[i][j]);
45         }
46     prim();
47     printf("%d",ans);
48 }

 1 #include<cstring>
 2 #include<cstdio>
 3 #include<algorithm>
 4 #include<vector>
 5 #include<cstdlib>
 6 using namespace std;
 7 const int MAXN=100000;
 8 vector<int> W[MAXN],E[MAXN];
 9 int dis[MAXN],ans=0,n,m,fa[MAXN];
10 bool vis[MAXN]={0};
11 struct edgee{
12     int u,v,w;
13 };
14 edgee edge[1000];
15 
16 int root(int now){
17     if (fa[now]!=now) fa[now]=root(fa[now]);
18     return fa[now];
19 }
20 
21 void kls(){
22     for (int i=0;i<m;i++){
23         if (root(edge[i].u)!=root(edge[i].v)) {
24             fa[root(edge[i].u)]=edge[i].v;
25             ans+=edge[i].w;
26         }
27     }
28 }
29 
30 int comp(const void*a,const void*b){
31     edgee*aa =(edgee*)a;
32     edgee*bb =(edgee*)b;
33     return aa->w>bb->w;
34 }
35 int main(){
36     scanf("%d%d",&n,&m);
37     int u,v,w1;
38     for (int i=1;i<=n;i++) fa[i]=i;
39     for (int i=0;i<m;i++){
40         scanf("%d%d%d",&edge[i].u,&edge[i].v,&edge[i].w);
41     }
42     qsort(edge,m,sizeof(edge[0]),comp);
43     kls();
44     printf("%d",ans);
45 }