public pcnPair <T> DeleteRightMinKeyNode()
{
if (IsRightEmpty())
{
throw new SBTNodeEmptyException(true);
}
if (this.Right.IsLeftEmpty())
{
BinarySearchTreeNode <T> buf = this.Right;
this.ChangeRightSubtree(buf.Right);
return(new pcnPair <T>(this, buf));
}
else
{
pcnPair <T> rmnPair = GetRightMinKeyNodePair();
if (rmnPair.cNode.IsRightEmpty())
{
rmnPair.pNode.RemoveLeftSubtree(); return(rmnPair);
}
else
{
rmnPair.pNode.ChangeLeftSubtree(rmnPair.cNode.Right); return(rmnPair);
}
}
}
public BinarySearchTreeNode <T> RemoveNode(U targetkey)
{
if (_rtnd == null)
{
throw new NotFound();
}
BinarySearchTreeNode <T> vNode = new BinarySearchTreeNode <T>(_rtnd.Data, null, _rtnd); //virtual node that is the parent of root node;
pcnPair <T> delPair = SearchPair(targetkey, vNode);
if (delPair.cNode.IsTerminal())
{
if (delPair.pNode.Left == delPair.cNode)
{
return((BinarySearchTreeNode <T>)delPair.pNode.RemoveLeftSubtree());
}
else
{
return((BinarySearchTreeNode <T>)delPair.pNode.RemoveRightSubtree());
}
}
else if (delPair.cNode.IsLeftEmpty())
{
delPair.cNode.Data = delPair.cNode.DeleteRightMinKeyNode().cNode.Data;
}
else
{
delPair.cNode.Data = delPair.cNode.DeleteLeftMaxKeyNode().cNode.Data;
}
_rtnd = vNode.Right;
vNode.Dispose();
return(delPair.cNode);
}
public pcnPair <T> DeleteLeftMaxKeyNode()
{
if (IsLeftEmpty())
{
throw new SBTNodeEmptyException(false);
}
if (this.Left.IsRightEmpty())
{
BinarySearchTreeNode <T> buf = this.Left;
this.ChangeLeftSubtree(buf.Left);
return(new pcnPair <T>(this, buf));
}
else
{
pcnPair <T> lmnPair = GetLeftMaxKeyNodePair();
if (lmnPair.cNode.IsLeftEmpty())
{
lmnPair.pNode.RemoveRightSubtree(); return(lmnPair);
}
else
{
lmnPair.pNode.ChangeRightSubtree(lmnPair.cNode.Left); return(lmnPair);
}
}
}
public pcnPair <T> SearchPair(U targetkey, BinarySearchTreeNode <T> vNode)
{
BinarySearchTreeNode <T> parent = vNode;
BinarySearchTreeNode <T> child = _rtnd;
U ckey;
while (child != null)
{
ckey = _gkey(child.Data);
if (targetkey.CompareTo(ckey) < 0)
{
parent = child; child = parent.Left;
}
else if (targetkey.CompareTo(ckey) > 0)
{
parent = child; child = parent.Right;
}
else
{
pcnPair <T> r = new pcnPair <T>(parent, child);
return(r);
}
}
throw new NotFound();
}
