Cod sursa(job #1813208)

Utilizator Y0da1NUME JMECHER Y0da1 Data 22 noiembrie 2016 19:56:24
Problema Cele mai apropiate puncte din plan Scor 10
Compilator cpp Status done
Runda Arhiva educationala Marime 2.33 kb
#include <iostream>
#include <algorithm>
#include <vector>
#include <fstream>
#include <iomanip>
#include <math.h>
using namespace std;
class punct{
public:
    int64_t x;
    int64_t y;

    bool operator <(const punct p2) const
    {
        return x < p2.x;
    }
};

float compareY(const punct a, const punct b)
{
    return (a.y < b.y);
}

punct v[100005], X[100005], Y[100005];
int N;

int64_t pldist(punct p1, punct p2)
{
    return /*sqrt*/( (p1.x - p2.x)*(p1.x - p2.x) +
                 (p1.y - p2.y)*(p1.y - p2.y)  );
}

float brutu(punct p[], int n)
{
    int64_t minim = 4e18;
    for (int i = 0; i < n; ++i)
        for (int j = i+1; j < n; ++j)
            if (pldist(p[i], p[j]) < minim)
                minim = pldist(p[i], p[j]);
    return minim;
}
int64_t minfasie(punct fasie[], int sz, int64_t dist)
{
    int64_t minim = dist;
    sort(fasie, fasie+sz, compareY);
    for (int i = 0; i < sz; ++i)
        for (int j = i+1; j < sz && (fasie[j].y - fasie[i].y) < minim; ++j)
            if (pldist(fasie[i],fasie[j]) < minim)
                minim = pldist(fasie[i], fasie[j]);

    return minim;
}
int64_t div_and_q(punct x[], punct y[], int n)
{
    if(n<4)
        return brutu(x, n);
    int mid = n/2;
    punct mijloc = x[mid]; //puncti prin care ducem o || la Oy
    punct yl[mid+1];   // y stanga
    punct yr[n-mid-1];  // y dreapta
    int li=0, ri=0;
    for (int i = 0; i < n; i++)
    {
      if (y[i].x <= mijloc.x)
      {
         yl[li] = y[i];
         ++li;
      }
      else
      {
         yr[ri] = y[i];
         ++ri;
      }
    }
    int64_t dl = div_and_q(x, yl, mid);
    int64_t dr = div_and_q(x + mid,yr, n-mid);
    int64_t dist = min(dl, dr);
    punct fasie [n];
    int j = 0;
    for (int i = 0; i < n; ++i)
        if (abs(y[i].x - mijloc.x) < dist)
        {
            fasie[j] = y[i];
            ++j;
        }
    return min(dist, minfasie(fasie, j, dist));
}

int main()
{

    ifstream in ("cmap.in");
    ofstream out ("cmap.out");
    int i;
    in>>N;
    for(i=0;i<N;++i)
    {
        in>>v[i].x>>v[i].y;
        X[i]=v[i];
        Y[i]=v[i];
    }
    sort(X, X+N);
    sort(Y, Y+N, compareY);

    out<<fixed<<setprecision(6)<<sqrt(div_and_q(X, Y, N));
    in.close();
    out.close();
    return 0;
}