/// <summary> This is a generic version of C.A.R Hoare's Quick Sort algorithm.
/// This will handle Sortable objects that are already
/// sorted, and Sortable objects with duplicate keys.
/// <p>
/// </summary>
/// <param name="sortable">A <code>Sortable</code> object.
/// </param>
/// <param name="lo0">Left boundary of partition.
/// </param>
/// <param name="hi0">Right boundary of partition.
/// </param>
public static void QuickSort(ISortable sortable, int lo0, int hi0)
{
int lo = lo0;
int hi = hi0;
IOrdered mid;
IOrdered test;
if (hi0 > lo0)
{
// arbitrarily establish partition element as the midpoint of the vector
mid = sortable.Fetch((lo0 + hi0) / 2, null);
test = null;
// loop through the vector until indices cross
while (lo <= hi)
{
// find the first element that is greater than or equal to
// the partition element starting from the left index
while ((lo < hi0) && (0 > (test = sortable.Fetch(lo, test)).Compare(mid)))
{
++lo;
}
// find an element that is smaller than or equal to
// the partition element starting from the right index
while ((hi > lo0) && (0 < (test = sortable.Fetch(hi, test)).Compare(mid)))
{
--hi;
}
// if the indexes have not crossed, swap
if (lo <= hi)
{
sortable.Swap(lo++, hi--);
}
}
// if the right index has not reached the left side of array
// must now sort the left partition
if (lo0 < hi)
{
QuickSort(sortable, lo0, hi);
}
// if the left index has not reached the right side of array
// must now sort the right partition
if (lo < hi0)
{
QuickSort(sortable, lo, hi0);
}
}
}
/// <summary> This is a generic version of C.A.R Hoare's Quick Sort algorithm.
/// This will handle Sortable objects that are already
/// sorted, and Sortable objects with duplicate keys.
/// <p>
/// </summary>
/// <param name="sortable">A <code>Sortable</code> object.
/// </param>
/// <param name="lo0">Left boundary of partition.
/// </param>
/// <param name="hi0">Right boundary of partition.
/// </param>
public static void QuickSort(ISortable sortable, int lo0, int hi0)
{
int lo = lo0;
int hi = hi0;
IOrdered mid;
IOrdered test;
if (hi0 > lo0)
{
// arbitrarily establish partition element as the midpoint of the vector
mid = sortable.Fetch((lo0 + hi0) / 2, null);
test = null;
// loop through the vector until indices cross
while (lo <= hi)
{
// find the first element that is greater than or equal to
// the partition element starting from the left index
while ((lo < hi0) && (0 > (test = sortable.Fetch(lo, test)).Compare(mid)))
++lo;
// find an element that is smaller than or equal to
// the partition element starting from the right index
while ((hi > lo0) && (0 < (test = sortable.Fetch(hi, test)).Compare(mid)))
--hi;
// if the indexes have not crossed, swap
if (lo <= hi)
sortable.Swap(lo++, hi--);
}
// if the right index has not reached the left side of array
// must now sort the left partition
if (lo0 < hi)
QuickSort(sortable, lo0, hi);
// if the left index has not reached the right side of array
// must now sort the right partition
if (lo < hi0)
QuickSort(sortable, lo, hi0);
}
}
