Building a Space Station
注意,这里的输出需要是%f型而不是%lf型的,否则wa.
#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<cmath>
#include<algorithm>
#include<vector>
using namespace std;
const int maxn=101;
int n;
struct node{
double x;
double y;
double z;
double r;
};
node cell[maxn];
struct edge{
int from;
int to;
double w;
bool operator<(const edge& t)const{
return w<t.w;
}
};
edge edges[5003];
int set[maxn];
int find(int x){
return x==set[x]?set[x]:set[x]=find(set[x]);
}
double kruskal(int es){
double sum=0.000;
for(int i=0;i<n;i++){
set[i]=i;
}
sort(edges,edges+es);
for(int i=0;i<es;i++){
int from=edges[i].from;
int to=edges[i].to;
double w=edges[i].w;
int x=find(from);
int y=find(to);
if(x!=y){
//cout<<from<<" "<<to<<" "<<w<<endl;
set[x]=y;
sum+=w;
}
}
return sum;
}
int main(){
while(cin>>n&&n){
for(int i=0;i<n;i++){
scanf("%lf%lf%lf%lf",&cell[i].x,&cell[i].y,&cell[i].z,&cell[i].r);
// cin>>cell[i].x>>cell[i].y>>cell[i].z>>cell[i].r;
}
int es=0;//边的数量
for(int i=0;i<n;i++){
for(int j=0;j<i;j++){
double radius=cell[i].r+cell[j].r;//半径之和
double distance=sqrt((cell[i].x-cell[j].x)*(cell[i].x-cell[j].x)+(cell[i].y-cell[j].y)*(cell[i].y-cell[j].y)+(cell[i].z-cell[j].z)*(cell[i].z-cell[j].z));
if(distance<=radius)//重叠
edges[es].from=i,edges[es].to=j,edges[es++].w=0.000;
else{
edges[es].from=i,edges[es].to=j,edges[es++].w=distance-radius;
}
//cout<<distance<<" ";
}
//cout<<endl;
}
double end=kruskal(es);
printf("%.3f\n",end);
}
return 0;
}