private static IEnumerable <TValue> InOrder(RbtNode <TKey, TValue> n)
{
if (n == Nil)
{
yield break;
}
if (n.Left != Nil)
{
foreach (var x in InOrder(n.Left))
{
yield return(x);
}
}
yield return(n.Value);
if (n.Right != Nil)
{
foreach (var x in InOrder(n.Right))
{
yield return(x);
}
}
}
private void RightRotate(RbtNode <TKey, TValue> node)
{
if (node.Left == Nil)
{
return;
}
var y = node.Left;
node.Left = y.Right;
if (y.Right != Nil)
{
y.Right.Parent = node;
}
y.Parent = node.Parent;
if (node.Parent == Nil)
{
_root = y;
}
else if (node == node.Parent.Left)
{
node.Parent.Left = y;
}
else
{
node.Parent.Right = y;
}
y.Right = node;
node.Parent = y;
}
private void InsertFixup(RbtNode <TKey, TValue> node)
{
while (node.Parent.IsRed)
{
if (node.Parent == node.Parent.Parent.Left)
{
var aunt = node.Parent.Parent.Right;
if (aunt.IsRed)
{
node.Parent.MarkBlack();
aunt.MarkBlack();
node.Parent.Parent.MarkRed();
node = node.Parent.Parent;
}
else
{
if (node == node.Parent.Right)
{
node = node.Parent;
LeftRotate(node);
}
node.Parent.MarkBlack();
node.Parent.Parent.MarkRed();
RightRotate(node.Parent.Parent);
}
}
else
{
var aunt = node.Parent.Parent.Left;
if (aunt.IsRed)
{
node.Parent.MarkBlack();
aunt.MarkBlack();
node.Parent.Parent.MarkRed();
node = node.Parent.Parent;
}
else
{
if (node == node.Parent.Left)
{
node = node.Parent;
RightRotate(node);
}
node.Parent.MarkBlack();
node.Parent.Parent.MarkRed();
LeftRotate(node.Parent.Parent);
}
}
}
_root.MarkBlack();
}
private RbtNode <TKey, TValue> MinOf(RbtNode <TKey, TValue> node)
{
var result = node;
var x = node;
while (x != Nil)
{
result = x;
x = x.Left;
}
return(result == Nil ? null : result);
}
private void Transplant(RbtNode <TKey, TValue> source, RbtNode <TKey, TValue> dest)
{
if (source.Parent == Nil)
{
_root = dest;
}
else if (source == source.Parent.Left)
{
source.Parent.Left = dest;
}
else
{
source.Parent.Right = dest;
}
dest.Parent = source.Parent;
}
public void Delete(RbtNode <TKey, TValue> node)
{
var y = node;
var yOrigColor = node.IsRed;
RbtNode <TKey, TValue> x;
if (node.Left == Nil)
{
x = node.Right;
Transplant(node, node.Right);
}
else if (node.Right == Nil)
{
x = node.Left;
Transplant(node, node.Left);
}
else
{
y = MinOf(node.Right);
yOrigColor = y.IsRed;
x = y.Right;
if (y.Parent == node)
{
x.Parent = y;
}
else
{
Transplant(y, y.Right);
y.Right = node.Right;
y.Right.Parent = y;
}
Transplant(node, y);
y.Left = node.Left;
y.Left.Parent = y;
y.IsRed = node.IsRed;
}
if (!yOrigColor) // if is black
{
DeleteFixup(x);
}
}
public RbtNode <TKey, TValue> Insert(TKey key, TValue value)
{
var node = new RbtNode <TKey, TValue>(key, value);
var parent = Nil;
var x = _root;
while (x != Nil)
{
parent = x;
var keyComparision = _keyComparer.Compare(node.Key, x.Key);
if (keyComparision < 0)
{
x = x.Left;
}
else
{
x = x.Right;
}
}
node.Parent = parent;
if (parent == Nil)
{
_root = node;
}
else if (_keyComparer.Compare(node.Key, parent.Key) < 0)
{
parent.Left = node;
}
else
{
parent.Right = node;
}
InsertFixup(node);
return(node);
}
private void DeleteFixup(RbtNode <TKey, TValue> node)
{
while (node != _root && node.IsBlack)
{
if (node == node.Parent.Left)
{
var brother = node.Parent.Right;
if (brother.IsRed)
{
brother.MarkBlack();
node.Parent.MarkRed();
LeftRotate(node.Parent);
brother = node.Parent.Right;
}
if (brother.Left.IsBlack && brother.Right.IsBlack)
{
brother.MarkRed();
node = node.Parent;
}
else
{
if (brother.Right.IsBlack)
{
brother.Left.MarkBlack();
brother.MarkRed();
RightRotate(brother);
brother = node.Parent.Right;
}
brother.IsRed = node.Parent.IsRed;
node.Parent.MarkBlack();
brother.Right.MarkBlack();
LeftRotate(node.Parent);
node = _root;
}
}
else
{
var brother = node.Parent.Left;
if (brother.IsRed)
{
brother.MarkBlack();
node.Parent.MarkRed();
RightRotate(node.Parent);
brother = node.Parent.Left;
}
if (brother.Right.IsBlack && brother.Left.IsBlack)
{
brother.MarkRed();
node = node.Parent;
}
else
{
if (brother.Left.IsBlack)
{
brother.Right.MarkBlack();
brother.MarkRed();
LeftRotate(brother);
brother = node.Parent.Left;
}
brother.IsRed = node.Parent.IsRed;
node.Parent.MarkBlack();
brother.Left.MarkBlack();
RightRotate(node.Parent);
node = _root;
}
}
}
}
public RbtNode(TKey key, TValue value, RbtNode <TKey, TValue> parent)
: this(key, value)
{
Parent = parent;
}
