/// <summary>
/// Create copyLL node in between of OriginalLL node and iterate two steps to set the right prev(random) path.
/// Time O(n) Space O(1)
/// </summary>
/// <param name="originalLL"></param>
/// <param name="copyLL"></param>
public static void CloneLinkedListInConstantSpace(DoublyLinkedList originalLL, DoublyLinkedList copyLL)
{
DoublyLinkedListNode originalLLNode = originalLL.Head;
DoublyLinkedListNode copyLLNode = null;
while (originalLLNode != null)
{//Iterate original LL
copyLLNode = new DoublyLinkedListNode(originalLLNode.data * -1);
copyLLNode.next = originalLLNode.next;
originalLLNode.next = copyLLNode;
originalLLNode = originalLLNode.next.next; // Move 2 steps ahead
}
//Each Copy Node is added between each original Node
originalLLNode = originalLL.Head;
while (originalLLNode != null)
{//Set prev (Random) node value and seperate two lists.
//Original next is Copy LLNode so use that to update prev of Copy LL node
originalLLNode.next.prev = originalLLNode.prev.next;
originalLLNode = originalLLNode.next.next;
}
originalLLNode = originalLL.Head;
//Set CopyList Head
copyLL.Head = originalLLNode.next;
copyLLNode = copyLL.Head;
while (originalLLNode != null)
{//Seperate Original and CopyList
originalLLNode.next = originalLLNode.next.next;
if (copyLLNode.next != null)
{
copyLLNode.next = copyLLNode.next.next;
}
else
{
copyLLNode.next = null;
}
originalLLNode = originalLLNode.next;
copyLLNode = copyLLNode.next;
}
}
//Not Implemented for Doubly
public DoublyLinkedListNode DeleteNode(DoublyLinkedListNode deleteNode)
{
if (head != null && head.data == deleteNode.data)
{
head = null;
}
else
{
DoublyLinkedListNode currentNode = head;
while (currentNode != null)
{
if (currentNode.next.data == deleteNode.data)
{
currentNode.next = currentNode.next.next;
break;
}
else
{
currentNode = currentNode.next;
}
}
}
return(head);
}
