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 AddLast(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 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 T RemoveLast()
{
if (count == 0)
{
throw new InvalidOperationException();
}
T output = tail.Data;
if (count == 1)
{
head = tail = null;
}
else
{
tail = tail.Previous;
tail.Next = null;
}
count--;
return(output);
}
public T RemoveFirst()
{
if (count == 0)
{
throw new InvalidOperationException();
}
T output = head.Data;
if (count == 1)
{
head = tail = null;
}
else
{
head = head.Next;
head.Previous = null;
}
count--;
return(output);
}
// 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 void Clear()
{
head = null;
tail = null;
count = 0;
}