Cod sursa(job #2491935)

Utilizator Natasa_CNatasa Cirstea Natasa_C Data 13 noiembrie 2019 16:19:10
Problema Cele mai apropiate puncte din plan Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.73 kb
#include <iostream>
#include <bits/stdc++.h>
#include <limits>
#include <vector>
#include <algorithm>
#include <fstream>
#include <climits>

using namespace std;

ifstream fin("cmap.in");
ofstream fout("cmap.out");

vector <pair<long long,long long> > v;

long long get_distance(pair <long long,long long> a,pair<long long,long long> b)
{
    return (a.first-b.first)*(a.first-b.first)+(a.second-b.second)*(a.second-b.second);
}


long long divide(long long st,long long dr)
{
    long long m, dist_min;

    if(dr-st<=3)
    {
        long long dist = LLONG_MAX ;
        for(int i=st; i<=dr; i++)
            for(int j=i+1; j<=dr; j++)
                dist = min(dist,get_distance(v[i],v[j]));

        return dist;
    }

    m = st + (dr - st) / 2;

    long long dist_s = divide(st,m);
    long long dist_d = divide(m+1,dr);

    dist_min = min(dist_s,dist_d);

    vector  < pair<long long,long long> > band;
    for(int i=st; i<=dr; i++)
        if(abs(v[m].first-v[i].first)<dist_min)
            band.push_back({v[i].second,v[i].first});

    sort(band.begin(),band.end());

    for(int i=0; i<band.size(); i++)
    {
        for(int j=i+1; j<band.size() &&  j < i + 8; j++)
        {
            long long dist = get_distance(band[i],band[j]);
            if(dist < dist_min)
                dist_min = dist;
        }
    }

    return dist_min;
}
int main()
{
    int n;
    long long x,y,dist_min;

    fin>>n;
    for(int i = 1; i <= n; i++)
    {
        fin>>x>>y;
        v.push_back({x,y});
    }

    sort(v.begin(),v.end());

    dist_min = divide(0,n-1);

    fout<<fixed<<setprecision(6)<<sqrt((double)dist_min);

    fin.close();
    fout.close();

    return 0;
}