hdu 1162 Eddy's picture

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
using namespace std;
const double INF=0xffffff;
double edge[105][105];
int nn,vis[105];
void prime(int x){
int i,j,k;
double sum_i,mark[105],mi_n;
for(i=1;i<=nn;i++){
mark[i]=edge[x][i];
vis[i]=0;
}
vis[x]=1;
sum_i=0;
for(i=1;i<=nn;i++){
mi_n=INF;
for(j=1;j<=nn;j++){
if(!vis[j]&&mark[j]<mi_n){
mi_n=mark[j];
k=j;
}
}
vis[k]=1;
if(mi_n!=INF)
sum_i+=mi_n;
for(j=1;j<=nn;j++){
if(!vis[j]&&edge[k][j]<mark[j])
mark[j]=edge[k][j];
}
}
printf("%.2lf\n",sum_i);
}
double jisuan(double x1,double y1,double x2,double y2){
return sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
}
int main(){
int i,j;
double x[105],y[105];
while(~scanf("%d",&nn)){
for(i=1;i<=nn;i++)
for(j=1;j<=nn;j++)
edge[i][j]=INF;
for(i=1;i<=nn;i++)
scanf("%lf %lf",&x[i],&y[i]);
for(i=1;i<=nn;i++)
for(j=i+1;j<=nn;j++){
double ans=jisuan(x[i],y[i],x[j],y[j]);
edge[i][j]=ans;
edge[j][i]=ans;
}
prime(1);
}
return 0;
}