// Suppose t != null.
void RemoveTarget(AvlSetNode <T> t)
{
if (t.TypedLeft == null || t.TypedRight == null)
{
var c = t.TypedLeft ?? t.TypedRight;
if (t.TypedParent == null)
{
Root = c;
}
else if (t.TypedParent.TypedLeft == t)
{
t.TypedParent.TypedLeft = c;
}
else
{
t.TypedParent.TypedRight = c;
}
t.TypedParent?.UpdateHeight(true);
}
else
{
var t2 = t.SearchNextNode() as AvlSetNode <T>;
t.Key = t2.Key;
RemoveTarget(t2);
}
}
AvlSetNode <T> Add(AvlSetNode <T> node, T item)
{
if (node == null)
{
++Count;
return(new AvlSetNode <T> {
Key = item
});
}
var d = compare(item, node.Key);
if (d == 0)
{
return(node);
}
if (d < 0)
{
node.TypedLeft = Add(node.TypedLeft, item);
}
else
{
node.TypedRight = Add(node.TypedRight, item);
}
var lrh = node.LeftHeight - node.RightHeight;
if (lrh > 2 || lrh == 2 && node.TypedLeft.LeftHeight >= node.TypedLeft.RightHeight)
{
node = node.RotateToRight() as AvlSetNode <T>;
node.TypedRight.UpdateHeight();
}
else if (lrh < -2 || lrh == -2 && node.TypedRight.LeftHeight <= node.TypedRight.RightHeight)
{
node = node.RotateToLeft() as AvlSetNode <T>;
node.TypedLeft.UpdateHeight();
}
node.UpdateHeight();
return(node);
}