private static RBNode NewNullNode()
{
var node = new RBNode(default(T));
node.ColorBlack();
return(node);
}
private void DeleteFix(RBNode node)
{
while (node != Root && node.IsBlack)
{
if (node == node.Parent.LeftChild)
{
var sibling = node.Parent.RightChild;
if (sibling.IsRed)
{
sibling.ColorBlack();
node.Parent.ColorRed();
RotateLeft(node.Parent);
sibling = node.Parent.RightChild;
}
if (sibling.LeftChild.IsBlack && sibling.RightChild.IsBlack)
{
sibling.ColorRed();
node = node.Parent;
}
else
{
if (sibling.RightChild.IsBlack)
{
sibling.ColorRed();
sibling.LeftChild.ColorBlack();
RotateRight(sibling);
sibling = node.Parent.RightChild;
}
sibling.RightChild.ColorBlack();
if (node.Parent.IsBlack)
{
sibling.ColorBlack();
}
else
{
sibling.ColorRed();
}
node.Parent.ColorBlack();
RotateLeft(node.Parent);
node = Root;
}
}
else // Repeat for RightChild case
{
var sibling = node.Parent.LeftChild;
if (sibling.IsRed)
{
sibling.ColorBlack();
node.Parent.ColorRed();
RotateRight(node.Parent);
sibling = node.Parent.LeftChild;
}
if (sibling.RightChild.IsBlack && sibling.LeftChild.IsBlack)
{
sibling.ColorRed();
node = node.Parent;
}
else
{
if (sibling.LeftChild.IsBlack)
{
sibling.ColorRed();
sibling.RightChild.ColorBlack();
RotateLeft(sibling);
sibling = node.Parent.LeftChild;
}
sibling.LeftChild.ColorBlack();
if (node.Parent.IsBlack)
{
sibling.ColorBlack();
}
else
{
sibling.ColorRed();
}
node.Parent.ColorBlack();
RotateRight(node.Parent);
node = Root;
}
}
}
node.ColorBlack();
}
