Cod sursa(job #1238623)

Utilizator romircea2010FMI Trifan Mircea Mihai romircea2010 Data 7 octombrie 2014 13:15:43
Problema Sortare prin comparare Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.31 kb
#include <iostream>
#include <fstream>
#include <cstdlib>
#include <ctime>

using namespace std;

const int NMax = 500010;
int n;
int a[NMax], aux[NMax];

void Read()
{
    ifstream f ("algsort.in");
    f >> n;
    for (int i = 1; i <= n; ++ i)
        f >> a[i];
    f.close();
}

inline void QuickSort(const int st, const int dr)
{
    if (dr - st < 1)
        return ;
    if (dr - st == 1)
    {
        if (a[st] > a[dr])
            swap(a[st], a[dr]);
        return ;
    }
    int poz = st + (rand() % (dr - st + 1));
    //int poz = (st+dr)/2;
    int pivot = a[poz];
    int l = st, r = dr;
    int count = 0;
    for (int i = st; i <= dr; ++ i)
    {
        if (a[i] < pivot)
        {
            aux[l++] = a[i];
            continue;
        }
        if (a[i] > pivot)
        {
            aux[r--] = a[i];
            continue;
        }
    }
    for (int i = l; i <= r; ++ i)
        aux[i] = pivot;
    for (int i = st; i <= dr; ++ i)
        a[i] = aux[i];

    QuickSort(st, l-1);
    QuickSort(r+1, dr);
}

void Write()
{
    ofstream g ("algsort.out");
    for (int i = 1; i <= n; ++ i)
        g << a[i] << " ";
    g << "\n";
    g.close();
}

int main()
{
    srand(time(NULL));
    Read();
    QuickSort(1, n);
    Write();
    return 0;
}