Cod sursa(job #2415518)

Utilizator Mihai145Oprea Mihai Adrian Mihai145 Data 26 aprilie 2019 10:22:34
Problema Cele mai apropiate puncte din plan Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.72 kb
#include <fstream>
#include <cmath>
#include <climits>
#include <algorithm>
#include <iomanip>

using namespace std;

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

const int NMAX = 100000;

struct pct
{
    long long x, y;

    bool operator < (const pct other) const
    {
        if(x == other.x)
            return y < other.y;

        return x < other.x;
    }
};

int N;
pct v[NMAX + 5], aux[NMAX + 5];

long long DMIN = LLONG_MAX;

long long Dist(pct A, pct B)
{
    return 1LL * (A.x - B.x) * (A.x - B.x) + (A.y - B.y) * (A.y - B.y);
}

void Merge(int l1, int r1, int l2, int r2)
{
    int k = 0;

    while(l1 <= r1 && l2 <= r2)
    {
        if(v[l1].y < v[l2].y)
            aux[++k] = v[l1], l1++;
        else
            aux[++k] = v[l2], l2++;
    }

    while(l1 <= r1)
        aux[++k] = v[l1], l1++;

    while(l2 <= r2)
        aux[++k] = v[l2], l2++;

    for(int i = r2; k > 0; k--, i--)
        v[i] = aux[k];
}

void DivideAndConquer(int l, int r)
{
    if(l >= r)
        return ;

    int mid = (l + r) >> 1;
    int d = v[mid].x;

    DivideAndConquer(l, mid);
    DivideAndConquer(mid + 1, r);

    Merge(l, mid, mid + 1, r);

    int k = 0;

    for(int i = l; i <= r; i++)
        if(1LL * (v[i].x - d) * (v[i].x - d) < DMIN)
            aux[++k] = v[i];

    for(int i = 1; i < k; i++)
        for(int j = i + 1; j <= k && j <= i + 8; j++)
            DMIN = min(DMIN, Dist(aux[i], aux[j]));
}

int main()
{
    fin >> N;

    for(int i = 1; i <= N; i++)
        fin >> v[i].x >> v[i].y;

    sort(v + 1, v + N + 1);

    DivideAndConquer(1, N);

    fout << fixed << setprecision(12) << sqrt(DMIN) << '\n';

    return 0;
}