Cod sursa(job #2240174)

Utilizator RaduXD1Nicolae Radu RaduXD1 Data 12 septembrie 2018 18:37:14
Problema Cele mai apropiate puncte din plan Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.35 kb
#include <fstream>
#include <algorithm>
#include <cmath>
#include <iomanip>
#define x first
#define y second
using namespace std;
ifstream fin ("cmap.in");
ofstream fout("cmap.out");
int n,i,f[100001];
pair<int,int> v[100001];

int cmp(int a, int b)
{
    return v[a].y<v[b].y;
}

double dist(int i, int j)
{
    long long x=1LL*(v[i].x-v[j].x)*(v[i].x-v[j].x)+1LL*(v[i].y-v[j].y)*(v[i].y-v[j].y);
    return sqrt(x);
}

double solve(int st, int dr)
{
    int i,j,mid;
    double mini=200000000000,aux;
    if(dr-st+1<=3)
    {
        for(i=st;i<dr;i++)
            for(j=i+1;j<=dr;j++)
            {
                aux=dist(i, j);
                if(mini>aux)
                    mini=aux;
            }
        return mini;

    }
    mid=(st+dr)/2;
    mini=min(solve(st, mid), solve(mid+1, dr));
    int k=0;
    for(i=mid;i>=st&&v[mid].x-v[i].x<=mini;i--)
        f[++k]=i;
    for(i=mid+1;i<=dr&&v[i].x-v[mid].x<=mini;i++)
        f[++k]=i;
    sort(f+1, f+k+1, cmp);
    for(i=1;i<=k;i++)
        for(j=i+1;j<=i+7&&j<=k;j++)
        {
            aux=dist(f[i], f[j]);
            if(mini>aux)
                mini=aux;
        }
    return mini;
}

int main(){
    fin>>n;
    for(i=1;i<=n;i++)
        fin>>v[i].x>>v[i].y;
    sort(v+1, v+n+1);
    fout<<setprecision(6)<<fixed<<solve(1, n);
    return 0;
}