思路：

分治

套路题

//By SiriusRen#include 
     
      #include 
      
       #include 
       
        using namespace std;const int N=100050;typedef double db;int n;struct P{db x,y;P(){}P(db X,db Y){x=X,y=Y;}}p[N],t[N];P operator-(P a,P b){
   return P(a.x-b.x,a.y-b.y);}db dis(P a){
    return sqrt(a.x*a.x+a.y*a.y);}bool cmp(P a,P b){
   return a.x
        
         >1,tp=0;    db d=min(solve(l,mid),solve(mid+1,r));    for(int i=l;i<=r;i++)if(p[i].x>=p[mid].x-d&&p[i].x<=p[mid].x+d)t[++tp]=p[i];    sort(t+1,t+1+tp,cmp2);    for(int i=1;i<=tp;i++){        for(int j=i+1;j<=tp;j++){            if(t[j].y>=t[i].y+d)break;            d=min(d,dis(t[i]-t[j]));        }    }    return d;}int main(){    while(scanf("%d",&n)&&n){        for(int i=1;i<=n;i++)scanf("%lf%lf",&p[i].x,&p[i].y);        sort(p+1,p+1+n,cmp);        printf("%.2lf\n",solve(1,n)/2);    }}