private BdNode <T> GetNode(int index)
{
if (index < 0 || index > _size)
{
throw new IndexOutOfRangeException("索引溢出或链表为空");
}
if (index < _size / 2)//正向查找
{
BdNode <T> node = _linkHead.Next;
for (int i = 0; i < index; i++)
{
node = node.Next;
}
return(node);
}
//方向查询
BdNode <T> rnode = _linkHead.Prev;
int rindex = _size - index - 1;
for (int i = 0; i < rindex; i++)
{
rnode = rnode.Prev;
}
return(rnode);
}
private int _size; //节点个数
public DoubleLink()
{
_linkHead = new BdNode <T>(default(T), null, null);
_linkHead.Prev = _linkHead;
_linkHead.Next = _linkHead;
_size = 0;
}
public void Del(int index)
{
BdNode <T> inode = GetNode(index);
inode.Prev.Next = inode.Next;
inode.Next.Prev = inode.Prev;
_size--;
}
// 将节点插入到第index位置之前
public void Insert(int index, T t)
{
if (_size < 1 || index >= _size)
{
throw new IndexOutOfRangeException("索引溢出或链表为空");
}
if (index == 0)
{
Append(_size, t);
}
else
{
BdNode <T> inode = GetNode(index);
BdNode <T> tnode = new BdNode <T>(t, inode.Prev, inode);
inode.Prev.Next = tnode;
inode.Prev = tnode;
_size++;
}
}
//追加到index位置之后
public void Append(int index, T t)
{
BdNode <T> inode;
if (index == 0)
{
inode = _linkHead;
}
else
{
index = index - 1;
if (index < 0)
{
throw new IndexOutOfRangeException("位置不存在");
}
inode = GetNode(index);
}
BdNode <T> tnode = new BdNode <T>(t, inode, inode.Next);
inode.Next.Prev = tnode;
inode.Next = tnode;
_size++;
}
public BdNode(T val, BdNode <T> prev, BdNode <T> next)
{
this.Data = val;
this.Prev = prev;
this.Next = next;
}
