最小圆覆盖模板

#include<bits/stdc++.h>
#define ll long long 
#define rep(i,a,b) for(int i=a;i<=b;i++)
#define rrp(i,a,b) for(int i=b;i>=a;i--)
#define dbg(x) cout<<#x<<"=="<<x<<endl 
#define eps 1e-8
using namespace std;
const int maxn=5e5+5;
int n;
double R,r;
struct Point{
    double x,y;
}p[maxn],ans;
int sgn(double x){
    if(fabs(x)<eps) return 0;
    else return x<0?-1:1;
}
double Distance(Point A,Point B){
    return hypot(A.x-B.x,A.y-B.y);
}
Point circle_center(const Point a,const Point b,const Point c){
    Point center;
    double a1=b.x-a.x,b1=b.y-a.y,c1=(a1*a1+b1*b1)/2;
    double a2=c.x-a.x,b2=c.y-a.y,c2=(a2*a2+b2*b2)/2;
    double d=a1*b2-a2*b1;
    center.x=a.x+(c1*b2-c2*b1)/d;
    center.y=a.y+(a1*c2-a2*c1)/d;
    return center;
}
void min_cover_circle(Point *p,int n,Point &c,double &r){
    random_shuffle(p+1,p+1+n);
    c=p[0];r=0;
    for(int i=1;i<=n;i++){
        if(sgn(Distance(p[i],c)-r)>0){
            c=p[i];r=0;
            for(int j=0;j<i;j++){
                if(sgn(Distance(p[j],c)-r)>0){
                    c.x=(p[i].x+p[j].x)/2;
                    c.y=(p[i].y+p[j].y)/2;
                    r=Distance(p[j],c);
                    for(int k=0;k<j;k++){
                        if(sgn(Distance(p[k],c)-r)>0){
                            c=circle_center(p[i],p[j],p[k]);
                            r=Distance(p[i],c);
                        }
                    }
                }
            }
        }
    }
    
}
int main()
{   
    freopen("robots.in","r",stdin);
    int t;
    scanf("%d",&t);
    while(t--){
        scanf("%d%d%d",&n,&R,&r);
        p[0]={0,0};
        rep(i,1,n){
            scanf("%lf%lf",&p[i].x,&p[i].y);
            p[i].x=p[i-1].x+p[i].x; 
            p[i].y=p[i-1].y+p[i].y;
        }
        min_cover_circle(p,n,ans,r);
        cout<<fixed<<setprecision(10)<<-ans.x<<" "<<-ans.y<<endl;
    }
    return 0; 
}