//Return node at the given index
public dNode <T> GetNode(int index)
{
if (index < 0 || index >= size)
{
throw new System.ArgumentException("Index out of bounds", "original");
}
else if (index == 0)
{
return(head);
}
else if (index == size - 1)
{
return(tail);
}
else
{
dNode <T> positionNode = head;
int position = 0;
while (position != index)
{
positionNode = positionNode.next;
position += 1;
}
return(positionNode);
}
}
//Insert element into the end of the DLL
public void InsertTail(T value)
{
dNode <T> newNode = new dNode <T>(value);
if (size == 0)
{
head = newNode;
tail = head;
}
else
{
newNode.prev = tail;
tail.next = newNode;
tail = newNode;
}
size += 1;
}
//Insert element into the beginning of DLL
public void InsertHead(T value)
{
dNode <T> newNode = new dNode <T>(value);
if (size == 0)
{
head = newNode;
tail = head;
}
else
{
newNode.next = head;
head.prev = newNode;
head = newNode;
}
size += 1;
}
//Delete element located at the given index. Throws exception if element is out of range.
public void DeleteAtIndex(int index)
{
if (index < 0 || index >= size)
{
throw new System.ArgumentException("Index out of bounds", "original");
}
else if (size == 1)
{
head = null;
tail = null;
size -= 1;
}
else if (index == 0)
{
head = head.next;
head.prev = null;
size -= 1;
}
else
{
dNode <T> positionNode = head;
int position = 0;
while (position != index)
{
positionNode = positionNode.next;
position += 1;
}
dNode <T> nextNode = positionNode.next;
dNode <T> prevNode = positionNode.prev;
//Delete at middle
if (nextNode != null)
{
prevNode.next = nextNode;
nextNode.prev = prevNode;
positionNode = null;
}
//Delete at tail
else
{
prevNode.next = null;
positionNode = null;
}
size--;
}
}
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);
}
//Insert element T into certain position of the DLL. Throws exception if element is out of range.
public void InsertAtIndex(int index, T value)
{
dNode <T> newNode = new dNode <T>(value);
dNode <T> positionNode = head;
int position = 0;
if (index < 0 || index > size)
{
throw new System.ArgumentException("Index out of bounds", "original");
}
else if (size == 0)
{
head = newNode;
tail = head;
size += 1;
}
else if (index == 0)
{
InsertHead(value);
}
else if (index == size)
{
InsertTail(value);
}
else
{
while (position != index)
{
positionNode = positionNode.next;
position += 1;
}
dNode <T> prevNode = positionNode.prev;
prevNode.next = newNode;
positionNode.prev = newNode;
newNode.next = positionNode;
newNode.prev = prevNode;
size += 1;
}
}
public DoublyLinkedList(T value)
{
head = new dNode <T>(value);
tail = head;
size = 1;
}
//Constructors for DoublyLinkedList
public DoublyLinkedList()
{
head = null;
tail = null;
size = 0;
}
//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;
}
}
}
public dNode(T value)
{
val = value;
next = null;
prev = null;
}
