public void Insert(int data)
{
RBTreeNode newNode;
RBTreeNode y = null;
RBTreeNode x;
if (Root == null) // Empty tree
{
Root = new RBTreeNode(data, red: false);
return;
}
newNode = new RBTreeNode(data); // Instantiate as Red node
x = Root;
// Traverse until y is a leaf in a location where x doesn’t violate
// the tree’s ordering
while (x != null)
{
y = x;
if (newNode < x)
{
x = x.Left();
}
else
{
x = x.Right();
}
}
// Make newNode child of y
newNode.SetParent(y);
if (newNode < y)
{
y.SetLeft(newNode);
}
else
{
y.SetRight(newNode);
}
RebalancePostInsertion(newNode);
}
private void RotateLeft(RBTreeNode x)
{
/**
* Make right subtree left subtree */
// setup x & y
RBTreeNode y = x.Right();
x.SetRight(y.Left());
// if y has a left child, make x the parent of the left child of y.
if (y.Left() != null)
{
y.Left().SetParent(x);
}
y.SetParent(x.Parent());
// if x has no parent, make y the root of the tree.
if (x.Parent() == null)
{
Root = y;
}
// else if x is the left child of p, make y the left child of p.
else if (x == x.Parent().Left())
{
x.Parent().SetLeft(y);
}
// else make y the right child of p
else
{
x.Parent().SetRight(y);
}
// make y the parent of x
y.SetLeft(x);
x.SetParent(y);
}
private void RotateRight(RBTreeNode y)
{
/**
* Make left subtree right subtree */
// setup x & y
RBTreeNode x = y.Left();
y.SetLeft(x.Right());
// if x has a right child, make y the parent of the right child of x.
if (x.Right() != null)
{
x.Right().SetParent(y);
}
x.SetParent(y.Parent());
// if y has no parent, make x the root of the tree.
if (y.Parent() == null)
{
Root = x;
}
// else if y is the right child of its parent p, make x the right child of p.
else if (y == y.Parent().Right())
{
y.Parent().SetRight(x);
}
// else assign x as the left child of p.
else
{
y.Parent().SetLeft(x);
}
// make x the parent of y.
x.SetRight(y);
y.SetParent(x);
}
private void Transplant(RBTreeNode oldNode, RBTreeNode newNode)
{
// Replace oldNode with newNode
RBTreeNode parent = oldNode.Parent();
if (parent == null)
{
Root = newNode;
}
else if (oldNode == parent.Left())
{
parent.SetLeft(newNode);
}
else
{
parent.SetRight(newNode);
}
// Null check for when newNode is null
if (newNode != null)
{
newNode.SetParent(parent);
}
}
