最小生成树kruskal+prim

 1 #include<cstdio> 
 2 #include<cstring>
 3 #include<cmath>
 4 #include<iostream>
 5 #include<algorithm>
 6 #include<queue>
 7 #include<set>
 8 #define maxint (2147483647)
 9 #define l(a) ((a)<<1)
10 #define r(a) ((a)<<1|1)
11 #define b(a) (2<<(a))
12 #define rep(i,a,b) for(int i=a;i<=(b);i++)
13 #define clr(a) memset(a,0,sizeof(a))
14 typedef long long ll;
15 using namespace std;
16 int readint(){
17     int t=0,f=1;char c=getchar();
18     while(!isdigit(c)){
19         if(c=='-') f=-1;
20         c=getchar();
21     }
22     while(isdigit(c)){
23         t=(t<<3)+(t<<1)+c-'0';
24         c=getchar();
25     }
26     return t*f;
27 }
28 const int maxn=5009,maxm=200009;
29 struct edge{
30     int u,v,w;
31     inline bool operator <(edge E)const{
32         return w<E.w;
33     }
34 }e[maxm];
35 int n,m,f[maxn];
36 int find(int x){
37     if(f[x]==x) return f[x];
38     return f[x]=find(f[x]);
39 }
40 int kruskal(){
41     int ans=0;
42     sort(e+1,e+m+1); 
43     rep(i,1,n) f[i]=i;
44     rep(i,1,m){
45         if(find(e[i].u)!=find(e[i].v)){
46             f[find(e[i].u)]=find(e[i].v);
47             ans+=e[i].w;
48         }
49     }
50     return ans;
51 }
52 int main(){
53     //freopen("#input.txt","r",stdin);
54     //freopen("#output.txt","w",stdout);
55     n=readint();m=readint();
56     rep(i,1,m){
57         e[i].u=readint();
58         e[i].v=readint();
59         e[i].w=readint();
60     }
61     cout<<kruskal()<<endl;
62     //fclose(stdin);
63     //fclose(stdout);
64     return 0;
65 }
kruskal
 1 #include<cstdio> 
 2 #include<cstring>
 3 #include<cmath>
 4 #include<ctime>
 5 #include<iostream>
 6 #include<algorithm>
 7 #include<queue>
 8 #include<set>
 9 #define maxint (2147483647)
10 #define l(a) ((a)<<1)
11 #define r(a) ((a)<<1|1)
12 #define b(a) (1<<(a))
13 #define rep(i,a,b) for(int i=a;i<=(b);i++)
14 #define clr(a) memset(a,0,sizeof(a))
15 typedef long long ll;
16 using namespace std;
17 int readint(){
18     int t=0,f=1;char c=getchar();
19     while(!isdigit(c)){
20         if(c=='-') f=-1;
21         c=getchar();
22     }
23     while(isdigit(c)){
24         t=(t<<3)+(t<<1)+c-'0';
25         c=getchar();
26     }
27     return t*f;
28 }
29 ll readll(){
30     ll t=0ll,f=1ll;char c=getchar();
31     while(!isdigit(c)){
32         if(c=='-') f=-1ll;
33         c=getchar();
34     }
35     while(isdigit(c)){
36         t=(t<<3ll)+(t<<1ll)+ll(c-'0');
37         c=getchar();
38     }
39     return t*f;
40 }
41 struct edge{
42     int v,w;
43     edge*next;
44     inline edge(int V,int W){
45         v=V;w=W;
46     }
47     inline edge(){}
48     inline bool operator<(const edge E)const{
49         return w>E.w||(w==E.w&&v>E.v);
50     }
51 };
52 const int maxn=1009,maxm=50009;
53 int n,m,t,ans;
54 bool p[maxn];
55 edge e[maxm],*pt=e,*fir[maxn];
56 priority_queue<edge>Q;
57 void add(int u,int v,int w){
58     pt->v=v;pt->w=w;pt->next=fir[u];
59     fir[u]=pt++;
60 }
61 void Dfs(int x){
62     p[x]=1;
63     for(edge*E=fir[x];E;E=E->next) if(!p[E->v]) Q.push(*E);
64     while(!Q.empty()&&p[Q.top().v]) Q.pop();
65     if(Q.empty()) return;
66     edge E=Q.top();Q.pop();
67     ans+=E.w;
68     Dfs(E.v);
69 }
70 int main(){
71     //freopen("#input.txt","r",stdin);
72     //freopen("#output.txt","w",stdout);
73     n=readint();m=readint();
74     rep(i,1,m){
75         int u=readint(),v=readint(),w=readint();
76         add(u,v,w);add(v,u,w);t+=w;
77     }
78     Dfs(1);
79     cout<<ans<<endl;
80     //fclose(stdin);
81     //fclose(stdout);
82     return 0;
83 }
prim

MST问题中注意加双向边!!!

上面的prim姿势好像有问题

 1 #include<cstdio> 
 2 #include<cstring>
 3 #include<cmath>
 4 #include<ctime>
 5 #include<iostream>
 6 #include<algorithm>
 7 #include<queue>
 8 #include<set>
 9 #define inf (0x7fffffff)
10 #define l(a) ((a)<<1)
11 #define r(a) ((a)<<1|1)
12 #define b(a) (1<<(a))
13 #define rep(i,a,b) for(int i=a;i<=(b);i++)
14 #define clr(a) memset(a,0,sizeof(a))
15 typedef long long ll;
16 typedef unsigned long long ull;
17 using namespace std;
18 int readint(){
19     int t=0,f=1;char c=getchar();
20     while(!isdigit(c)){
21         if(c=='-') f=-1;
22         c=getchar();
23     }
24     while(isdigit(c)){
25         t=(t<<3)+(t<<1)+c-'0';
26         c=getchar();
27     }
28     return t*f;
29 }
30 const int maxn=5009;
31 struct node{
32     double x,y;
33     inline void in(){
34         x=readint();y=readint();
35     }
36 }x[maxn];
37 double dis(int a,int b){
38     return sqrt((x[a].x-x[b].x)*(x[a].x-x[b].x)+(x[a].y-x[b].y)*(x[a].y-x[b].y));
39 }
40 struct edge{
41     int v;
42     double w;
43     inline edge(int V,double W){
44         v=V;w=W;
45     }    
46     inline bool operator<(const edge A)const{
47         return w>A.w;
48     }
49 };
50 int n;
51 double ans,d[maxn];
52 bool p[maxn];
53 priority_queue<edge>Q;
54 void cal(){
55     int cnt=0;
56     rep(i,1,n) d[i]=1e10;d[1]=0;Q.push(edge(1,0));
57     while(!Q.empty()){
58         while(p[Q.top().v]) Q.pop();
59         edge e=Q.top();Q.pop();
60         cnt++;p[e.v]=1;ans+=e.w;
61         if(cnt==n) break;
62         rep(i,1,n) if(!p[i]){
63             double tmp=dis(i,e.v);
64             if(d[i]>tmp){
65                 Q.push(edge(i,tmp));
66                 d[i]=tmp;
67             }
68         }
69     }
70     printf("%.2lf\n",ans);
71 }
72 int main(){
73     //freopen("#input.txt","r",stdin);
74     //freopen("#output.txt","w",stdout);
75     n=readint();
76     rep(i,1,n) x[i].in();
77     cal();
78     //fclose(stdin);
79     //fclose(stdout);
80     return 0;
81 }
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posted @ 2017-10-14 10:15  ChenThree  阅读(105)  评论(0编辑  收藏  举报