// Basic Insert function - Uses polymorphism
public void Insert(RBNode node, RBTree tree)
{
node = (RBNode)base.Insert(node, tree);
if (node == null)
{
return;
}
// Add the NilNodes as leaves
node.LChild = NilNode;
node.RChild = NilNode;
// If we are inserting the root, make it black, otherwise, make it red
if (node.Parent == null)
{
node.Parent = NilNode;
node.NodeColor = COLOR.BLACK;
}
else
{
node.NodeColor = COLOR.RED;
}
// Fix-Up
FixUpRB(tree, node);
}
// Fix nodes
public void FixUpRB(RBTree tree, RBNode N)
{
while (parent(N).NodeColor == COLOR.RED)
{
// If parent(N) is an LChild of grandparent(N)
if (parent(N) == grandparent(N).LChild)
{
// Y is the uncle of Node N
RBNode Y = (RBNode)grandparent(N).RChild;
// Case 1: RED Uncle,
if (Y.NodeColor == COLOR.RED)
{
// Make the parent and uncle black
parent(N).NodeColor = COLOR.BLACK;
Y.NodeColor = COLOR.BLACK;
grandparent(N).NodeColor = COLOR.RED;
N = grandparent(N);
}
// Case 2: BLACK Uncle
else
{
if (N == parent(N).RChild)
{
N = parent(N);
LeftRotate(N);
}
parent(N).NodeColor = COLOR.BLACK;
grandparent(N).NodeColor = COLOR.RED;
RightRotate(grandparent(N));
}
}
else
{
// Y is the uncle of Node N
RBNode Y = (RBNode)grandparent(N).LChild;
// Case 1: RED Uncle,
if (Y.NodeColor == COLOR.RED)
{
// Make the parent and uncle black
parent(N).NodeColor = COLOR.BLACK;
Y.NodeColor = COLOR.BLACK;
grandparent(N).NodeColor = COLOR.RED;
N = grandparent(N);
}
// Case 2: BLACK Uncle
else
{
if (N == parent(N).LChild)
{
N = parent(N);
RightRotate(N);
}
parent(N).NodeColor = COLOR.BLACK;
grandparent(N).NodeColor = COLOR.RED;
LeftRotate(grandparent(N));
}
}
}
// Color it black
((RBNode)tree.root).NodeColor = COLOR.BLACK;
}
