//O(n)
public void InsertAtIndex(int value, int index)
{
if (index > count - 1)
{
throw new IndexOutOfRangeException();
}
DLLNode newNode = new DLLNode(value);
DLLNode leader = head;
int i = 0;
while (leader != null)
{
if (index == i)
{
//at the index [1 3 *99* 5 7 9]
//want to insert between follower(3) and leader(5)
//follower = 3, leader 5, newNode = 99
DLLNode follower = leader.Previous;
follower.Next = newNode;
newNode.Previous = follower;
newNode.Next = leader;
leader.Previous = newNode;
count++;
}
leader = leader.Next;
i++;
}
}
public DoublyLinkedList(int value)
{
DLLNode newNode = new DLLNode(value);
head = newNode;
tail = head;
count++;
}
//O(1)
public void InsertAtTail(int value)
{
DLLNode newNode = new DLLNode(value);
DLLNode oldTail = tail;
newNode.Previous = oldTail;
oldTail.Next = newNode;
tail = newNode;
count++;
}
//O(1)
public void InsertAtHead(int value)
{
DLLNode newNode = new DLLNode(value);
DLLNode oldHead = head;
head = newNode;
newNode.Next = oldHead;
oldHead.Previous = newNode;
count++;
}
//O(n)
public void Display()
{
Console.WriteLine("The Doubly Linked List consist of:");
DLLNode temp = head;
while (temp != null)
{
Console.Write(temp.Value + " ");
temp = temp.Next;
}
Console.WriteLine();
}
//O(n)
public bool IsPresent(int value)
{
DLLNode temp = head;
while (temp != null)
{
if (temp.Value == value)
{
return(true);
}
temp = temp.Next;
}
return(false);
}
//O(n)
public void Delete(int value)
{
DLLNode temp = head;
while (temp != null)
{
if (temp.Value == value)
{
DLLNode nodeToDelete = temp;
DLLNode follower = temp.Previous;
DLLNode leader = temp.Next;
follower.Next = leader;
leader.Previous = follower;
nodeToDelete.Previous = null;
nodeToDelete.Next = null;
count--;
return;
}
temp = temp.Next;
}
}
