void qsort(int a[], int lo, int hi) {
{
 int h, l, p, t;

 if (lo < hi) {
 l = lo;
 h = hi;
 p = a[hi];

 do {
 while ((l < h) && (a[l] <= p)) 
 l = l+1;
 while ((h > l) && (a[h] >= p))
 h = h-1;
 if (l < h) {
 t = a[l];
 a[l] = a[h];
 a[h] = t;
 }
 } while (l < h);

 t = a[l];
 a[l] = a[hi];
 a[hi] = t;

 qsort( a, lo, l-1 );
 qsort( a, l+1, hi );
 }
}