public void Traverse()
{
Console.WriteLine("######### Traverse Linklist #########");
DoubleLinkListNode current = header;
while (current != null)
{
Console.WriteLine(current.data);
current = current.next;
}
}
public void InsertNodeAtBegining(int value)
{
DoubleLinkListNode node = new DoubleLinkListNode(value);
if (header.next != null)
{
node.next = header.next;
header.next.previous = node;
}
header = node;
}
public void InsertNodeBefore(int value, int before)
{
DoubleLinkListNode current = Find(before);
if (current != null)
{
DoubleLinkListNode node = new DoubleLinkListNode(value);
node.next = current;
node.previous = current.previous;
current.previous.next = node;
current.previous = node;
}
}
public void InsertNodeAtEnd(int value)
{
DoubleLinkListNode node = new DoubleLinkListNode(value);
DoubleLinkListNode current = header;
while (current.next != null)
{
current = current.next;
}
node.previous = current;
current.next = node;
}
public void TraverseBackward()
{
Console.WriteLine("######### Traverse Backward #########");
DoubleLinkListNode current = header;
while (current.next != null)
{
current = current.next;
}
while (current != null)
{
Console.WriteLine(current.data);
current = current.previous;
}
}
public void DeleteNode(int value)
{
DoubleLinkListNode current = Find(value);
if (current != null)
{
current.previous.next = current.next;
if (current.next != null)
{
current.next.previous = current.previous;
}
current = null;
}
}
public void InsertNodeAfter(int value, int after)
{
DoubleLinkListNode current = Find(after);
if (current != null)
{
DoubleLinkListNode node = new DoubleLinkListNode(value);
if (current.next != null)
{
node.next = current.next;
current.next.previous = node;
}
node.previous = current;
current.next = node;
}
}
public DoubleLinkListNode Find(int value)
{
DoubleLinkListNode current = header;
while (current != null)
{
if (current.data == value)
{
break;
}
else
{
current = current.next;
}
}
return(current);
}
public void IsListCircular()
{
DoubleLinkListNode fast = header;
DoubleLinkListNode slow = header;
if (header == null || header.next == null)
{
Console.WriteLine("List is not circular");
}
while (true)
{
fast = fast.next.next;
slow = slow.next;
if (fast == null || fast.next == null)
{
Console.WriteLine("List is not circular");
return;
}
else if (fast == slow || fast.next == slow)
{
Console.WriteLine("List is circular");
slow = header;
while (true)
{
if (slow == fast)
{
Console.WriteLine("Circular link list start from: " + slow.data);
return;
}
else
{
fast = fast.next.next;
slow = slow.next;
}
}
}
}
}
private void doublelinklist_Click(object sender, EventArgs e)
{
DoubleLinkList list = new DoubleLinkList();
list.InsertNodeAtBegining(1);
list.InsertNodeAfter(3, 1);
list.InsertNodeBefore(2, 3);
list.InsertNodeAtEnd(4);
list.InsertNodeAtEnd(5);
list.InsertNodeAfter(6, 5);
list.DeleteNode(3);
list.Traverse();
list.TraverseBackward();
//Make list circular
DoubleLinkListNode second = list.Find(2);
DoubleLinkListNode node = list.Find(6);
node.next = second;
list.IsListCircular();
}
public DoubleLinkList()
{
header = new DoubleLinkListNode();
}
