最基础的最小生成树，简单题。
View Code
1 #include <stdio.h> 2 #include <math.h> 3 #include <stdlib.h> 4 #define D(x1,y1,x2,y2) (sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2))) 5 #define N 100 6 #define M 5000 7 struct node 8 { 9 int a,b; 10 double d; 11 }edge[M]; 12 int n,m; 13 double x[N],y[N]; 14 int p[M]; 15 void make_set() 16 { 17 int i; 18 for(i=0;i<m;i++) p[i]=i; 19 } 20 int find_set(int i) 21 { 22 return i==p[i]?p[i]:(p[i]=find_set(p[i])); 23 } 24 int union_set(int i,int j) 25 { 26 i=p[i],j=p[j]; 27 p[j]=i; 28 } 29 int cmp(void const *a,void const *b) 30 { 31 return ((struct node*)a)->d-((struct node*)b)->d>0?1:-1; 32 } 33 int main() 34 { 35 int t,i,j; 36 double ans; 37 scanf("%d",&t); 38 while(t--) 39 { 40 scanf("%d",&n); 41 for(i=0;i<n;i++) 42 { 43 scanf("%lf%lf",&x[i],&y[i]); 44 } 45 m=0; 46 for(i=0;i<n;i++) 47 { 48 for(j=i+1;j<n;j++) 49 { 50 edge[m].a=i,edge[m].b=j; 51 edge[m++].d=D(x[i],y[i],x[j],y[j]); 52 } 53 } 54 make_set(); 55 qsort(edge,m,sizeof(edge[0]),cmp); 56 for(i=0,ans=0;i<m;i++) 57 { 58 if(find_set(edge[i].a)==find_set(edge[i].b)) continue; 59 union_set(edge[i].a,edge[i].b); 60 ans+=edge[i].d; 61 } 62 printf("%.2lf\n",ans); 63 if(t) printf("\n"); 64 } 65 return 0; 66 }