Cod sursa(job #765539)

Utilizator BlaugranasEnal Gemaledin Blaugranas Data 8 iulie 2012 00:44:23
Problema Cele mai apropiate puncte din plan Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1 kb
#include<cstdio>
#include<cmath>
#include<algorithm>
using namespace std;
#define M 1000000
struct P
{double x,y;};
P a[100001];
int i,n;

int A(P a,P b)
{return a.x<b.x||(a.x==b.x&&a.y<b.y);}

double B(P p,P q)
{return ((p.x-q.x)/M)*((p.x-q.x)/M)+((p.y-q.y)/M)*((p.y-q.y)/M);}

double C(int p,int m,int q,double r)
{int i,j,l,t;
for(i=m;i<=q&&a[i].x-a[m].x<r&&i<=m+7;i++);
for(j=m;j>=p&&a[m].x-a[j].x<r&&j>=m-7;j--);
for(l=j+1;l<i;l++)
for(t=l+1;t<=i;t++)
if(r>B(a[l],a[t]))
       r=B(a[l],a[t]);
return r;}

double D(int p,int q)
{int m=(p+q)>>1,i,j;
double d,t,c,b;
if(q-p<4)
       {t=B(a[p],a[p+1]);
       for(i=p;i<q;i++)
       for(j=i+1;j<=q;j++)
       if(t>(d=B(a[i],a[j])))
             t=d;
       return t;}
return C(p,m,q,(c=D(p,m))<(b=D(m+1,q))?c:b);}

int main()
{freopen("cmap.in","r",stdin);
freopen("cmap.out","w",stdout);
scanf("%d",&n);
for(i=1;i<=n;i++)
       scanf("%lf%lf",&a[i].x,&a[i].y);
sort(a+1,a+n+1,A);
printf("%.6lf\n",D(1,n));
return 0;}