int FindPivot(int A[],int l, int r)
{
    switch (choice) {
       case 1: return l;
       case 2: return pivot2(A,l,h)
       case 3: return l+random(r-l);
    }
}

int partition(int A[], int l, int r)
{
   int i,pivot, pivotpos;

   pivotpos    = FindPivot(A,l,r);
   swap(&A[l],&A[pivotpos]);
   pivotpos = l;
   pivot = A[pivotpos];

   for (i = l+1; i <= r; i++) {
     if (A[i] < pivot) {
        pivotpos++;
        swap(&A[pivotpos],&A[i]);
     }
   }

   swap(&A[l],&A[pivotpos]);
   return pivotpos;
}

void QuickSort(int A[], int l,int r, 
               int threshold)
{
  int i, pivot;

  if (r-l>threshold) {
     delay(CompareDelay);
     pivot = partition(A,l,r);
 
     QuickSort(A,l,pivot-1,threshold);
     QuickSort(A,pivot+1,r,threshold);
  }
}

int pivot2(int A[], int l, int r)
{
  int i = (r+l)/2;

  if ((A[l] <= A[i]) && (A[i] <= A[r]))
     return i;
  if ((A[r] <= A[i]) && (A[i] <= A[l]))
     return i;
  if ((A[r] <= A[l]) && (A[l] <= A[i]))
     return l;
  if ((A[i] <= A[l]) && (A[l] <= A[r]))
     return l;
  if ((A[l] <= A[r]) && (A[r] <= A[i]))
     return r;
  if ((A[i] <= A[r]) && (A[r] <= A[l]))
     return r;
}