Cod sursa(job #1362181)

Utilizator ArmandNMArmand Nicolicioiu ArmandNM Data 26 februarie 2015 10:52:08
Problema Cele mai apropiate puncte din plan Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.54 kb
#include <fstream>
#include <algorithm>
#include <iomanip>
#include <cmath>
#include <vector>

const int NMAX = 100005;
const int inf = 0x3f3f3f3f;

using namespace std;

ifstream f("cmap.in");
ofstream g("cmap.out");

struct pct
{
    int x;
    int y;
};

pct p[NMAX];

int N;

bool cmp(pct a, pct b)
{
    if (a.x == b.x)
        return (a.y < b.y);

    return a.x < b.x;
}

double dist(pct a, pct b)
{
    return sqrt(1LL*(a.x-b.x)*(a.x-b.x) + 1LL*(a.y-b.y)*(a.y-b.y));
}

double minim(double a, double b)
{
    if (a < b)
        return a;
    return b;
}

double maxim(double a, double b)
{
    if (a > b)
        return a;
    return b;
}

double solve(int l, int r)
{
    if (l == r)
        return inf;
    if (r == l+1)
        return dist(p[l],p[r]);

    double S;

    int mid = (l+r) / 2;

    S = minim(solve(l,mid),solve(mid+1,r));

    vector <pct> Y;

    for (int i = l; i <= r; ++i)
    {
        if (maxim( p[i].x-p[mid].x, p[mid].x-p[i].x ) <= S)
        {
            Y.push_back(p[i]);
        }
    }

    for (int i = 0; i < Y.size(); ++i)
    {
        for (int j = i+1; j <= i+7 && j < Y.size(); ++j)
        {
            if (dist(Y[i],Y[j]) < S)
                S = dist(Y[i],Y[j]);
        }
    }

    return S;
}

int main()
{
    f >> N;
    for (int i = 1; i <= N; ++i)
    {
        f >> p[i].x >> p[i].y;
    }

    sort(p+1,p+N+1,cmp);

    g << fixed << setprecision(6) << solve(1,N);

    f.close();
    g.close();

    return 0;
}