public DoublyLinkedList(T initialValue)
{
DoublyNode <T> initialNode = new DoublyNode <T>
{
Value = initialValue,
Next = null,
Previous = null
};
Head = initialNode;
Tail = initialNode;
}
public DoublyNode <T> Find(T val)
{
DoublyNode <T> pos = Head;
while (pos != null)
{
if (pos.Value.Equals(val))
{
return(pos);
}
pos = pos.Next;
}
return(null);
}
//removefirst
public bool RemoveFirst()
{
if (Count == 0)
{
return(false);
}
DoublyNode <T> temp = Head;
Head = Head.Next;
temp.Next = null;
Head.Prev = Tail;
Tail.Next = Head;
Count--;
return(true);
}
public void PrintListForwards()
{
Console.WriteLine("---------------------------------------------->");
DoublyNode <T> temp = Head;
while (true)
{
Console.WriteLine(temp.Value);
temp = temp.Next;
if (temp == Head)
{
break;
}
}
Console.WriteLine("<----------------------------------------------");
}
public void PrintListBackwards()
{
Console.WriteLine("---------------------------------------------->");
DoublyNode <T> temp = Tail;
while (true)
{
Console.WriteLine(temp.Value);
temp = temp.Prev;
if (temp == Tail)
{
break;
}
}
Console.WriteLine("<----------------------------------------------");
}
public void InsertBegin <U>(U value) where U : T
{
DoublyNode <T> newNode = new DoublyNode <T>()
{
Value = value,
};
if (Head == null)
{
Head = newNode;
Tail = newNode;
newNode.Previous = null;
newNode.Next = null;
}
else
{
InsertBefore(Head, value);
}
}
public void InsertAfter(DoublyNode <T> node, T value)
{
DoublyNode <T> newNode = new DoublyNode <T>()
{
Value = value,
Previous = node
};
if (node.Next == null)
{
Tail = newNode;
}
else
{
newNode.Next = node.Next;
node.Next.Previous = newNode;
}
node.Next = newNode;
}
//addlast
public void AddLast(T val)
{
if (Head == null)
{
Head = new DoublyNode <T>(val);
Tail = Head;
Head.Prev = Tail;
Tail.Next = Head;
}
else
{
var temp = new DoublyNode <T>(val);
Tail.Next = temp;
temp.Prev = Tail;
Tail = temp;
Tail.Next = Head;
Head.Prev = Tail;
}
Count++;
}
// addfirst
public void AddFirst(T val)
{
if (Head == null)
{
Head = new DoublyNode <T>(val);
Tail = Head;
Tail.Next = Head;
Head.Prev = Tail;
}
else
{
DoublyNode <T> temp = new DoublyNode <T>(val);
temp.Next = Head;
Head.Prev = temp;
Head = temp;
Head.Prev = Tail;
Tail.Next = Head;
}
Count++;
}
public void InsertBefore(DoublyNode <T> node, T value)
{
DoublyNode <T> newNode = new DoublyNode <T>()
{
Value = value,
Next = node
};
if (node.Previous == null)
{
newNode.Previous = null;
Head = newNode;
}
else
{
newNode.Next = node;
node.Previous.Next = newNode;
}
node.Previous = newNode;
}
//addafter
public void AddAfter(DoublyNode <T> Node, T val)
{
if (Node == null)
{
AddLast(val);
return;
}
else if (Node == Tail)
{
AddLast(val);
return;
}
DoublyNode <T> temp = new DoublyNode <T>(val);
temp.Prev = Node;
temp.Next = Node.Next;
Node.Next.Prev = temp;
Node.Next = temp;
Count++;
}
public bool RemoveLast()
{
if (Head == null)
{
return(false);
}
else if (Head == Tail)
{
Head = null;
Tail = Head;
return(true);
}
DoublyNode <T> temp = Tail.Prev;
temp.Next = null;
Tail = temp;
Tail.Next = Head;
Head.Prev = Tail;
Count--;
return(true);
}
//addbefore
public void AddBefore(DoublyNode <T> Node, T val)
{
if (Node == null)
{
AddLast(val);
return;
}
else if (Node == Head)
{
AddFirst(val);
return;
}
DoublyNode <T> temp = new DoublyNode <T>(val);
var nodeBefore = Node.Prev;
nodeBefore.Next = temp;
temp.Next = Node;
temp.Prev = nodeBefore;
Node.Prev = temp;
Count++;
}
// remove
public bool Remove(T val)
{
if (val.Equals(Head.Value))
{
RemoveFirst();
return(true);
}
else if (val.Equals(Tail.Value))
{
RemoveLast();
return(true);
}
else if (val == null)
{
throw new ArgumentException();
}
DoublyNode <T> item = Find(val);
item.Prev.Next = item.Next;
item.Next.Prev = item.Prev;
Count--;
return(true);
}
/// <summary>
/// Return whether or not the queue contains a certain value somewhere in the queue
/// </summary>
/// <param name="value"></param>
/// <returns></returns>
public bool Contains(T value)
{
if (list.Head == null)
{
return(false);
}
DoublyNode <T> currentNode = list.Head;
if (list.Head.Value.Equals(value))
{
return(true);
}
while (currentNode.Next != null)
{
if (currentNode.Next.Value.Equals(value))
{
return(true);
}
currentNode = currentNode.Next;
}
return(false);
}
public DoublyNode(T val)
{
Value = val;
Next = null;
}
public DoublyLinkedLIists()
{
Count = 0;
Head = null;
Tail = null;
}