public IEnumerable <T> BackEnumerator()
{
DoublyNode <T> current = tail;
while (current != null)
{
yield return(current.Data);
current = current.Previous;
}
}
IEnumerator <T> IEnumerable <T> .GetEnumerator()
{
DoublyNode <T> current = head;
while (current != null)
{
yield return(current.Data);
current = current.Next;
}
}
public bool Contains(T data)
{
DoublyNode <T> current = head;
while (current != null)
{
if (current.Data.Equals(data))
{
return(true);
}
current = current.Next;
}
return(false);
}
int count; // количество элементов в списке
// добавление элемента
public void Add(T data)
{
DoublyNode <T> node = new DoublyNode <T>(data);
if (head == null)
{
head = node;
}
else
{
tail.Next = node;
node.Previous = tail;
}
tail = node;
count++;
}
public void RemoveFirst()
{
if (Count != 0)
{
Head = Head.Next;
Count--;
if (Count == 0)
{
Tail = null;
}
else
{
Head.Prev = null;
}
}
}
public void AddLast(DoublyNode <T> node)
{
if (Count == 0)
{
Head = node;
}
else
{
Tail.Next = node;
node.Prev = Tail;
}
Tail = node;
Count++;
}
public void AddFirst(T data)
{
DoublyNode <T> node = new DoublyNode <T>(data);
DoublyNode <T> temp = head;
node.Next = temp;
head = node;
if (count == 0)
{
tail = head;
}
else
{
temp.Previous = node;
}
count++;
}
public void RemoveLast()
{
if (Count != 0)
{
if (Count == 1)
{
Head = null;
Tail = null;
}
else
{
Tail.Prev.Next = null;
Tail = Tail.Prev;
}
Count--;
}
}
// удаление элемента
public bool Remove(T data)
{
DoublyNode <T> current = head;
DoublyNode <T> removedItem = null;
if (count == 0)
{
return(false);
}
// поиск удаляемого узла
do
{
if (current.Data.Equals(data))
{
removedItem = current;
break;
}
current = current.Next;
}while (current != head);
if (removedItem != null)
{
// если удаляется единственный элемент списка
if (count == 1)
{
head = null;
}
else
{
// если удаляется первый элемент
if (removedItem == head)
{
head = head.Next;
}
removedItem.Previous.Next = removedItem.Next;
removedItem.Next.Previous = removedItem.Previous;
}
count--;
return(true);
}
return(false);
}
public void AddFirst(DoublyNode <T> node)
{
var temp = Head;
Head = node;
Head.Next = temp;
Count++;
if (Count == 1)
{
Tail = Head;
}
else
{
temp.Prev = Head;
}
}
public virtual void Add(T value)
{
if (head == null)
{
head = new DoublyNode <T>(value);
return;
}
DoublyNode <T> temp = (DoublyNode <T>)head;
while (temp.Next != null)
{
temp = (DoublyNode <T>)temp.Next;
}
temp.Next = new DoublyNode <T>(value);
DoublyNode <T> temp2 = temp;
temp = (DoublyNode <T>)temp.Next;
temp.Previous = temp2;
}
int count; // количество элементов в списке
// добавление элемента
public void Add(T data)
{
DoublyNode <T> node = new DoublyNode <T>(data);
if (head == null)
{
head = node;
head.Next = node;
head.Previous = node;
}
else
{
node.Previous = head.Previous;
node.Next = head;
head.Previous.Next = node;
head.Previous = node;
}
count++;
}
// удаление
public bool Remove(T data)
{
DoublyNode <T> current = head;
// поиск удаляемого узла
while (current != null)
{
if (current.Data.Equals(data))
{
break;
}
current = current.Next;
}
if (current != null)
{
// если узел не последний
if (current.Next != null)
{
current.Next.Previous = current.Previous;
}
else
{
// если последний, переустанавливаем tail
tail = current.Previous;
}
// если узел не первый
if (current.Previous != null)
{
current.Previous.Next = current.Next;
}
else
{
// если первый, переустанавливаем head
head = current.Next;
}
count--;
return(true);
}
return(false);
}
public bool Remove(T item)
{
DoublyNode <T> prev = null;
DoublyNode <T> current = Head;
while (current != null)
{
if (current.Value.Equals(item))
{
if (prev != null)
{
prev.Next = current.Next;
if (current.Next == null)
{
Tail = prev;
}
else
{
current.Next.Prev = prev;
}
Count--;
}
else
{
RemoveFirst();
}
return(true);
}
prev = current;
current = current.Next;
}
return(false);
}
public void Clear()
{
head = null;
tail = null;
count = 0;
}
public DoublyLinkedList(T initialValue)
{
head = new DoublyNode <T>(initialValue);
}
public void Clear()
{
Head = null;
Tail = null;
Count = 0;
}
