1. 程式人生 > >hdu 3007【最小圓覆蓋-隨機增量法】

hdu 3007【最小圓覆蓋-隨機增量法】

names cpp dia printf include const n) shu ons

#include<iostream>
#include<cstdio>
#include<cmath>
#include<algorithm>
using namespace std;
const int N=505;
int n;
double r;
struct dian
{
    double x,y;
    dian(double X=0,double Y=0)
    {
        x=X,y=Y;
    }
    dian operator + (const dian &a) const
    {
        return
dian(x+a.x,y+a.y); } dian operator - (const dian &a) const { return dian(x-a.x,y-a.y); } dian operator * (const double &a) const { return dian(x*a,y*a); } dian operator / (const double &a) const { return dian(x/a,y/a); } }p[N],c; double
dis(dian a,dian b) { return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y)); } double cj(dian a,dian b) { return a.x*b.y-a.y*b.x; } dian yx(dian a,dian b,dian c) { dian p=b-a,q=c-a; double c1=(p.x*p.x+p.y*p.y)/2,c2=(q.x*q.x+q.y*q.y)/2,d=cj(p,q); return a+dian(c1*q.y-c2*p.y,c2*p.x-c1*q.x)/d; } int
main() { while(scanf("%d",&n)&&n) { for(int i=1;i<=n;i++) scanf("%lf%lf",&p[i].x,&p[i].y); random_shuffle(p+1,p+1+n); c=p[1],r=0; for(int i=2;i<=n;i++) if(dis(p[i],c)-r>0) { c=p[i],r=0; for(int j=1;j<i;j++) if(dis(p[j],c)-r>0) { c=(p[i]+p[j])/2,r=dis(p[j],c); for(int k=1;k<j;k++) if(dis(p[k],c)-r>0) c=yx(p[i],p[j],p[k]),r=dis(p[k],c); } } printf("%.2f %.2f %.2f\n",c.x,c.y,r); } return 0; }

hdu 3007【最小圓覆蓋-隨機增量法】