ural 1640 Circle of Winter

#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#define maxn 3000
using namespace std;

struct node
{
int x,y;
}p[300];
double sqr(double x)
{
return x*x;
}
bool vis[maxn];
double dis(int x1,int y1,int x2,int y2)
{
return sqrt(sqr(x1-x2)+sqr(y1-y2));
}
int main()
{
int n;
scanf("%d",&n);
memset(vis,false,sizeof(vis));
for(int i=0; i<n; i++)
{
scanf("%d%d",&p[i].x,&p[i].y);
vis[p[i].x]=true;
}
int x,y;
for(int i=0; i<=maxn; i++)
{
if(!vis[i])
{
x=i;
y=0;
break;
}
}
double max1=-1;
for(int i=0; i<n; i++)
{
max1=max(max1,dis(p[i].x,p[i].y,x,y));
}
printf("%d %d %.9lf\n",x,y,max1);
return 0;
}