program-6.cpp

/* 
Randomized Quick Sort
*/

#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;

int partition(int a[], int low, int high) {
    int pivot = a[high];
    int i = low - 1;

    for (int j = low; j < high; j++) {
        if (a[j] < pivot) {
            i++;
            swap(a[i], a[j]);
        }
    }

    swap(a[i + 1], a[high]);

    return i + 1;
}

int randomPartition(int a[], int low, int high) {
    int p = low + rand() % (high - low + 1);

    swap(a[p], a[high]);

    return partition(a, low, high);
}

void quickSort(int a[], int low, int high) {
    if (low < high) {
        int pi = randomPartition(a, low, high);

        quickSort(a, low, pi - 1);
        quickSort(a, pi + 1, high);
    }
}

int main() {
    srand(time(0));

    int n;
    cin >> n;

    int a[n];

    for (int i = 0; i < n; i++)
        cin >> a[i];

    quickSort(a, 0, n - 1);

    for (int i = 0; i < n; i++)
        cout << a[i] << " ";

    return 0;
}