private void RemoveTail()
{
if (tail == null)
{
return;
}
index.Remove(tail.Key);
if (head == tail)
{
head = tail = null;
return;
}
tail.Pre.Next = null;
tail = tail.Pre;
}
private DListNode <TKey, TValue> InsetToHead(TValue value)
{
var node = new DListNode <TKey, TValue>()
{
Value = value
};
if (head == null)
{
head = node;
tail = node;
}
else
{
node.Next = head;
head.Pre = node;
head = node;
}
return(node);
}
private void MoveToHead(DListNode <TKey, TValue> node)
{
if (node == head)
{
return;
}
node.Pre.Next = node.Next;
if (node == tail)
{
tail = node.Pre;
}
else
{
node.Next.Pre = node.Pre;
}
node.Pre = null;
node.Next = head;
head.Pre = node;
head = node;
}
