/* Adapted from http://24bytes.com/Quick-Sort.html */
int partition(int a[], int p, int r)
{
        int x, j;
        int i;

    x = a [r];
    j = p - 1;
    for (i = p; i < r; i++) {

        if (x <= a[i]) {
                int temp;
            j = j + 1;
            temp = a[j];
            a[j] = a[i];
            a[i] = temp;
        }

    }

    a[r] = a[j + 1];
    a[j + 1] = x;

    return (j + 1);
}

void quickSort(int a[], int p, int r)
{
        int q;

    if (p < r) {
        q = partition(a, p, r);
        quickSort(a, p, q - 1);
        quickSort(a, q + 1, r);
    }
}