Cod sursa(job #336654)

Utilizator DastasIonescu Vlad Dastas Data 31 iulie 2009 23:57:48
Problema Sortare prin comparare Scor 20
Compilator cpp Status done
Runda Arhiva educationala Marime 1.31 kb
#include <fstream>
#include <cstdlib>
#include <algorithm>

using namespace std;

ifstream in("algsort.in");
ofstream out("algsort.out");

int Partitie(int A[], int st, int dr)
{
    int poz = st + (rand() % (dr - st + 1));
    int tmp = A[poz];
    A[poz] = A[st];
    A[st] = tmp;

    int V = A[st];
    while ( st < dr )
    {
        while ( A[dr] > V )
            --dr;
        while ( A[st] < V )
            ++st;

        if ( st < dr )
        {
            int tmp = A[st];
            A[st] = A[dr];
            A[dr] = tmp;
            --dr; ++st;
        }
    }

    return dr;
}

void Quicksort(int A[], int st, int dr)
{
    while ( st < dr )
    {
        if ( dr - st + 1 < 200 )
        {
            sort(A+st, A+dr+1);
            return;
        }

        int P = Partitie(A, st, dr);
        if ( P - st < dr - P )
        {
            Quicksort(A, st, P - 1);
            st = P + 1;
        }
        else
        {
            Quicksort(A, P + 1, dr);
            dr = P;
        }
    }
}

int A[500020];
int main()
{
    int n;
    srand((unsigned)time(0));

    in >> n;
    for ( int i = 1; i <= n; ++i )
        in >> A[i];
    Quicksort(A, 1, n);

    for ( int i = 1; i <= n; ++i )
        out << A[i] << " ";

    return 0;
}