private void RightRotate(RBTNode <T> node)
{
var left = node.Left;
node.Left = left.Right;
if (left.Right != null)
{
left.Right.Parent = node;
}
left.Parent = node.Parent;
if (node.Parent == null)
{
root = left;
}
else if (node == node.Parent.Right)
{
node.Parent.Right = left;
}
else
{
node.Parent.Left = left;
}
left.Right = node;
node.Parent = left;
}
private void LeftRotate(RBTNode <T> node)
{
var right = node.Right;
node.Right = right.Left;
if (right.Left != null)
{
right.Left.Parent = node;
}
right.Parent = node.Parent;
if (node.Parent == null)
{
root = right;
}
else if (node == node.Parent.Left)
{
node.Parent.Left = right;
}
else
{
node.Parent.Right = right;
}
right.Left = node;
node.Parent = right;
}
private RBTNode <T> Minimum(RBTNode <T> node)
{
while (node.Left != null)
{
node = node.Left;
}
return(node);
}
private void GetInOrder(RBTNode <T> node, LinkedList <T> nodeList)
{
if (node != null)
{
GetInOrder(node.Left, nodeList);
nodeList.InsertBack(node.Value);
GetInOrder(node.Right, nodeList);
}
}
private void InsertFixup(RBTNode <T> node)
{
while (node.Parent != null && node.Parent.Color == RBTColor.Red)
{
if (node.Parent == node.Parent.Parent.Left)
{
var uncle = node.Parent.Parent?.Right;
if (uncle != null && uncle.Color == RBTColor.Red)
{
node.Parent.Color = RBTColor.Black;
uncle.Color = RBTColor.Black;
node.Parent.Parent.Color = RBTColor.Red;
node = node.Parent.Parent; // iterate
}
else
{
if (node == node.Parent.Right)
{
node = node.Parent;
LeftRotate(node); // "hoist"
}
node.Parent.Color = RBTColor.Black;
node.Parent.Parent.Color = RBTColor.Red;
RightRotate(node.Parent.Parent); // "lower"
}
}
else
{
var uncle = node.Parent.Parent?.Left;
if (uncle != null && uncle.Color == RBTColor.Red)
{
node.Parent.Color = RBTColor.Black;
uncle.Color = RBTColor.Black;
node.Parent.Parent.Color = RBTColor.Red;
node = node.Parent.Parent; // iterate
}
else
{
if (node == node.Parent.Left)
{
node = node.Parent;
RightRotate(node); // "hoist"
}
node.Parent.Color = RBTColor.Black;
node.Parent.Parent.Color = RBTColor.Red;
LeftRotate(node.Parent.Parent); // "lower"
}
}
}
root.Color = RBTColor.Black;
}
public void Insert(T value)
{
var v = new RBTNode <T>(value)
{
Color = RBTColor.Red
};
var node = root;
while (node != null)
{
var result = Comparer <T> .Default.Compare(v.Value, node.Value);
if (result <= 0)
{
if (node.Left == null)
{
node.Left = v;
node.Left.Parent = node;
Count++;
InsertFixup(node.Left);
return;
}
else
{
node = node.Left;
}
}
else
{
if (node.Right == null)
{
node.Right = v;
node.Right.Parent = node;
Count++;
InsertFixup(node.Right);
return;
}
else
{
node = node.Right;
}
}
}
root = v;
Count++;
InsertFixup(root);
}
private void Transplant(RBTNode <T> uproot, RBTNode <T> plant)
{
if (uproot.Parent == null)
{
root = plant;
}
else if (uproot == uproot.Parent.Left)
{
uproot.Parent.Left = plant;
}
else
{
uproot.Parent.Right = plant;
}
if (plant != null)
{
plant.Parent = uproot.Parent;
}
}
private void RemoveFixup(RBTNode <T> node)
{
while (node != null && node != root && node.Color == RBTColor.Black)
{
if (node == node.Parent.Left)
{
var sibling = node.Parent.Right;
if (sibling.Color == RBTColor.Red)
{
sibling.Color = RBTColor.Black;
node.Parent.Color = RBTColor.Red;
LeftRotate(node.Parent);
sibling = node.Parent.Right;
}
if (sibling.Left != null &&
sibling.Left.Color == RBTColor.Black &&
sibling.Right != null &&
sibling.Right.Color == RBTColor.Black)
{
sibling.Color = RBTColor.Red;
node = node.Parent; // iterate
}
else
{
if (sibling.Right.Color == RBTColor.Black)
{
sibling.Left.Color = RBTColor.Black;
sibling.Color = RBTColor.Red;
RightRotate(sibling);
sibling = node.Parent.Right;
}
sibling.Color = node.Parent.Color;
node.Parent.Color = RBTColor.Black;
sibling.Right.Color = RBTColor.Black;
LeftRotate(node.Parent);
node = root;
}
}
else
{
var sibling = node.Parent.Left;
if (sibling.Color == RBTColor.Red)
{
sibling.Color = RBTColor.Black;
node.Parent.Color = RBTColor.Red;
RightRotate(node.Parent);
sibling = node.Parent.Left;
}
if (sibling.Left != null &&
sibling.Left.Color == RBTColor.Black &&
sibling.Right != null &&
sibling.Right.Color == RBTColor.Black)
{
sibling.Color = RBTColor.Red;
node = node.Parent; // iterate
}
else
{
if (sibling.Left.Color == RBTColor.Black)
{
sibling.Right.Color = RBTColor.Black;
sibling.Color = RBTColor.Red;
LeftRotate(sibling);
sibling = node.Parent.Left;
}
sibling.Color = node.Parent.Color;
node.Parent.Color = RBTColor.Black;
sibling.Left.Color = RBTColor.Black;
RightRotate(node.Parent);
node = root;
}
}
}
if (node != null)
{
node.Color = RBTColor.Black;
}
}