public static bool IsCircular(DoublyLinkedListNode <T> head)
{
// 필터링 하면서 내려가면서 마지막까지 없으면 false
if (head is null)
{
return(true);
}
var current = head;
for ( ; current != null;)
{
current = current.Next;
if (current == head)
{
return(true);
}
}
return(false);
}
public void Add(DoublyLinkedListNode <T> newNode)
{
if (_head is null)
{
_head = newNode;
_head.Next = _head;
_head.Prev = _head;
}
else
{
var current = _head;
var tail = _head.Prev;
// urrent.Next이 for문을 돌 때마다
// 1. 현재 값의 다음 값을 계속 불러온다.
// 추가할 때 양 방향 연결
current.Prev = newNode;
tail.Next = newNode;
newNode.Prev = tail;
newNode.Next = current;
}
}
public void Remove(DoublyLinkedListNode <T> removeNode)
{
if (_head is null || removeNode is null)
{
return;
}
if (removeNode == _head)
{
removeNode = _head.Next;
if (_head != null)
{
_head.Prev = null;
}
}
else
{
removeNode.Prev.Next = removeNode.Next;
removeNode.Next.Prev = removeNode.Prev;
}
removeNode = null;
}
public bool IsHeadNull(DoublyLinkedListNode <T> head)
{
return(_head is null);
}