OJ-Problems-Source/HDOJ/3932_autoAC.cpp

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#include <cstdio>
#include <cmath>
#include <time.h>
#include <cstdlib>
using namespace std;
const double pi=acos(-1.0);
const int maxn=1005;
double x[maxn], y[maxn];
int n;
double dis2 (double x1,double y1 ,double x2,double y2)
{
double tmp1=x1-x2,tmp2=y1-y2;
tmp1*=tmp1;
tmp2*=tmp2;
return tmp1+tmp2;
}
double test(double xx, double yy)
{
double max = 0,tmp;
for (int i=0;i<n;i++)
if(max<(tmp=dis2(xx,yy,x[i],y[i])))max=tmp;
return max;
}
int main()
{
double xx,yy;
double delta,theta;
double X,Y;
double retx,rety,ans;
while (~scanf("%lf%lf%d",&X,&Y,&n))
{
for (int i=0 ; i<n ; i++)
scanf("%lf%lf",x+i,y+i);
double ans=1000000000.0;
for (int i=0 ; i<10 ; ++i)
{
xx=((double)(rand()%1001)/1000.0)*X;
yy=((double)(rand()%1001)/1000.0)*Y;
double dis=test(xx,yy);
for (delta=X ; delta>0.001 ; delta*=0.9)
{
for (theta=0 ; theta<=2*pi ; theta+=(pi/25.0))
{
double tx=xx+delta*cos(theta);
double ty=yy+delta*sin(theta);
double tdis=test(tx,ty);
if(tdis<dis)
{
xx=tx;
yy=ty;
dis=tdis;
}
}
}
if(dis<ans)
{
retx=xx;
rety=yy;
ans=dis;
}
}
printf("(%.1lf,%.1lf).\n%.1lf\n",retx,rety,sqrt(ans));
}
return 0;
}