Cod sursa(job #1092447)

Utilizator mihai995mihai995 mihai995 Data 27 ianuarie 2014 01:17:02
Problema Sortare prin comparare Scor 20
Compilator cpp Status done
Runda Arhiva educationala Marime 1.42 kb
#include <fstream>
using namespace std;

const int N = 5e5;
const int Size = 8, Mask = (1 << Size) - 1;

int v[N], pos[1 + Mask], n;

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

void selSort(int st, int dr){
    for (int i = st ; i < dr ; i++)
        for (int j = i + 1 ; j <= dr ; j++)
            if (v[i] > v[j])
                swap(v[i], v[j]);
}

int median(int st, int dr){
    int p, i;
    while (st != dr){
        for (i = st, p = st ; p + 5 <= dr ; p += 5, i++){
            selSort(p, p + 4);
            swap(v[i], v[p + 2]);
        }
        if (p != dr){
            selSort(p, dr);
            swap(v[i], v[(p + dr) >> 1]);
        } else
            i--;
        dr = i;
    }
    return v[st];
}

void qsort(int st, int dr){
    if (dr - st <= 20)
        return selSort(st, dr);

    int i = st, j = dr, p = median(st, dr);
    while (v[i] != p || v[j] != p){
        while (v[i] < p) i++;
        while (p < v[j]) j--;
        swap(v[i], v[j]);
    }
    for (int k = i ; k < j ; k++){
        if (v[k] < p)
            swap(v[k], v[i++]);
        if (p < v[k])
            swap(v[k], v[j--]);
    }
    qsort(st, i - 1);
    qsort(j + 1, dr);
}

int main(){
    in >> n;
    for (int i = 0 ; i < n ; i++)
        in >> v[i];

    qsort(0, n - 1);

    for (int i = 0 ; i < n ; i++)
        out << v[i] << " ";
    out << "\n";

    return 0;
}