hud1007 Quoit Design

#include<algorithm>
#include<iostream>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<string>
#include<cmath>
#include<ctime>
#include<queue>
#include<stack>
#include<map>
#include<set>
#define rre(i,r,l) for(int i=(r);i>=(l);i--)
#define re(i,l,r) for(int i=(l);i<=(r);i++)
#define Clear(a,b) memset(a,b,sizeof(a))
#define inout(x) printf("%d",(x))
#define douin(x) scanf("%lf",&x)
#define strin(x) scanf("%s",(x))
#define LLin(x) scanf("%lld",&x)
#define op operator
#define CSC main
typedef unsigned long long ULL;
typedef const int cint;
typedef long long LL;
using namespace std;
double f(const long double &a){return a*a;}
const double inf=2147483647;
void inin(int &ret)
{
    ret=0;int f=0;char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')f=1;ch=getchar();}
    while(ch>='0'&&ch<='9')ret*=10,ret+=ch-'0',ch=getchar();
    ret=f?-ret:ret;
}
struct xl
{
    double x,y;
    void in(){douin(x),douin(y);}
    xl(double x=0,double y=0):x(x),y(y){}
    bool op < (const xl &rhs)const {return x==rhs.x?y<rhs.y:x<rhs.x;}
};
xl di[100010];
int wocao[100010];
int n,top;
bool com(const int &a,const int &b)
{
    return di[a].y<di[b].y;
}
double dis(const xl &a,const xl &b)
{
    return sqrt(f(a.x-b.x)+f(a.y-b.y));
}
double mindis(int l,int r)
{
    double ret=inf;
    if(l==r)return ret;
    if(r-l+1<=3)
    {
        re(i,l,r)re(j,i+1,r)
            ret=min(ret,dis(di[i],di[j]));
        return ret;
    }
    int mid=(l+r)>>1;
    ret=min(mindis(l,mid),mindis(mid+1,r));
    top=0;
    re(i,l,r)
    {
        double temp=abs(di[mid].x-di[i].x);
        if(temp<=ret)wocao[++top]=i;
    }
    sort(wocao+1,wocao+top+1,com);
    re(i,1,top)
        re(j,i+1,top)
        {
            if(di[wocao[j]].y-di[wocao[i]].y>=ret)break;
            ret=min(ret,dis(di[wocao[i]],di[wocao[j]]));
        }
    top=0;
    return ret;
}
int main()
{
    while(~scanf("%d",&n)&&n)
    {
        re(i,1,n)di[i].in();
        sort(di+1,di+n+1);
        printf("%.2f
",mindis(1,n)/2);
    }
     return 0;
}