private int Partition(int begin, int end)
{
dNode <T> pivot = GetNode(end);
int i = begin - 1;
for (int j = begin; j < end; j++)
{
if (GetNode(j).GetValue().CompareTo(pivot.GetValue()) < 0)
{
i++;
Swap(i, j);
}
}
Swap(i + 1, end);
return(i + 1);
}
//Swap two elements in the DLL
public void Swap(int first, int second)
{
//If one of the elements is out of range throw exception
if (first < 0 || second < 0 || first >= size || second >= size)
{
throw new System.ArgumentException("Index out of bounds", "original");
}
//If elements are equal no swap required
else if (first != second)
{
dNode <T> firstNode = GetNode(first);
dNode <T> secondNode = GetNode(second);
dNode <T> temp = new dNode <T>(firstNode.GetValue());
temp.next = firstNode.next;
temp.prev = firstNode.prev;
//If elements are consecutive
if (firstNode.prev == secondNode)
{
if (secondNode.prev != null)
{
if (firstNode.next != null)
{
firstNode.next.prev = secondNode;
}
firstNode.prev = secondNode.prev;
secondNode.prev.next = firstNode;
secondNode.next = firstNode.next;
secondNode.prev = firstNode;
firstNode.next = secondNode;
}
else
{
if (firstNode.next != null)
{
firstNode.next.prev = secondNode;
}
secondNode.next = firstNode.next;
secondNode.prev = firstNode;
firstNode.next = secondNode;
firstNode.prev = null;
head = firstNode;
}
}
else if (firstNode.next == secondNode)
{
Swap(second, first);
}
//If elements are different
else
{
if (firstNode.prev != null)
{
dNode <T> firstPrev = firstNode.prev;
firstPrev.next = secondNode;
}
else
{
head = secondNode;
}
if (firstNode.next != null)
{
dNode <T> firstNext = firstNode.next;
firstNext.prev = secondNode;
}
else
{
tail = secondNode;
}
if (secondNode.prev != null)
{
dNode <T> secondPrev = secondNode.prev;
secondPrev.next = firstNode;
}
else
{
head = firstNode;
}
if (secondNode.next != null)
{
dNode <T> secondNext = secondNode.next;
secondNext.prev = firstNode;
}
else
{
tail = firstNode;
}
firstNode.next = secondNode.next;
firstNode.prev = secondNode.prev;
secondNode.next = temp.next;
secondNode.prev = temp.prev;
}
}
}
