private void New(TKey key, TValue data)
{
if (data == null)
{
throw new Exception();
}
// create new node
var newNode = new RedBlackNode <TKey, TValue>(key, data);
var workNode = _root;
while (!workNode.IsSentinel)
{
// find Parent
newNode.Parent = workNode;
int result = key.CompareTo(workNode.Key);
if (result == 0)
{
throw new Exception();
}
workNode = result > 0
? workNode.Right
: workNode.Left;
}
// insert node into tree starting at parent's location
if (newNode.Parent != null)
{
if (newNode.Key.CompareTo(newNode.Parent.Key) > 0)
{
newNode.Parent.Right = newNode;
}
else
{
newNode.Parent.Left = newNode;
}
}
else
{
_root = newNode;
}
// restore red-black properties
BalanceTreeAfterInsert(newNode);
}
private static int MaxDepthInternal(RedBlackNode <TKey, TValue> node)
{
if (node.IsSentinel)
{
return(0);
}
/* compute the depth of each subtree */
var lDepth = MaxDepthInternal(node.Left);
var rDepth = MaxDepthInternal(node.Right);
/* use the larger one */
if (lDepth > rDepth)
{
return(lDepth + 1);
}
return(rDepth + 1);
}
private bool isValidRBT(RedBlackNode <TKey, TValue> node, TKey low, TKey high)
{
if (node.IsSentinel)
{
return(true);
}
bool isLow = false;
bool isHigh = false;
if (node.Key.CompareTo(low) > 0)
{
isLow = true;
}
if (node.Key.CompareTo(high) < 0)
{
isHigh = true;
}
return(isLow && isHigh &&
isValidRBT(node.Left, low, node.Key) &&
isValidRBT(node.Right, node.Key, high));
}
private void RotateLeft(RedBlackNode <TKey, TValue> rotateNode)
{
var workNode = rotateNode.Right;
rotateNode.Right = workNode.Left;
if (!workNode.Left.IsSentinel)
{
workNode.Left.Parent = rotateNode;
}
if (!workNode.IsSentinel)
{
workNode.Parent = rotateNode.Parent;
}
if (rotateNode.Parent != null)
{
if (rotateNode == rotateNode.Parent.Left)
{
rotateNode.Parent.Left = workNode;
}
else
{
rotateNode.Parent.Right = workNode;
}
}
else
{
_root = workNode;
}
workNode.Left = rotateNode;
if (!rotateNode.IsSentinel)
{
rotateNode.Parent = workNode;
}
}
private void BalanceTreeAfterDelete(RedBlackNode <TKey, TValue> linkedNode)
{
while (linkedNode != _root && linkedNode.Color == RedBlackNodeType.Black)
{
RedBlackNode <TKey, TValue> workNode;
if (linkedNode == linkedNode.Parent.Left)
{
workNode = linkedNode.Parent.Right;
if (workNode.Color == RedBlackNodeType.Red)
{
linkedNode.Parent.Color = RedBlackNodeType.Red;
workNode.Color = RedBlackNodeType.Black;
RotateLeft(linkedNode.Parent);
workNode = linkedNode.Parent.Right;
}
if (workNode.Left.Color == RedBlackNodeType.Black &&
workNode.Right.Color == RedBlackNodeType.Black)
{
workNode.Color = RedBlackNodeType.Red;
linkedNode = linkedNode.Parent;
}
else
{
if (workNode.Right.Color == RedBlackNodeType.Black)
{
workNode.Left.Color = RedBlackNodeType.Black;
workNode.Color = RedBlackNodeType.Red;
RotateRight(workNode);
workNode = linkedNode.Parent.Right;
}
workNode.Color = linkedNode.Parent.Color;
linkedNode.Parent.Color = RedBlackNodeType.Black;
workNode.Right.Color = RedBlackNodeType.Black;
RotateLeft(linkedNode.Parent);
linkedNode = _root;
}
}
else
{ // right subtree - same as code above with right and left swapped
workNode = linkedNode.Parent.Left;
if (workNode.Color == RedBlackNodeType.Red)
{
linkedNode.Parent.Color = RedBlackNodeType.Red;
workNode.Color = RedBlackNodeType.Black;
RotateRight(linkedNode.Parent);
workNode = linkedNode.Parent.Left;
}
if (workNode.Right.Color == RedBlackNodeType.Black &&
workNode.Left.Color == RedBlackNodeType.Black)
{
workNode.Color = RedBlackNodeType.Red;
linkedNode = linkedNode.Parent;
}
else
{
if (workNode.Left.Color == RedBlackNodeType.Black)
{
workNode.Right.Color = RedBlackNodeType.Black;
workNode.Color = RedBlackNodeType.Red;
RotateLeft(workNode);
workNode = linkedNode.Parent.Left;
}
workNode.Color = linkedNode.Parent.Color;
linkedNode.Parent.Color = RedBlackNodeType.Black;
workNode.Left.Color = RedBlackNodeType.Black;
RotateRight(linkedNode.Parent);
linkedNode = _root;
}
}
}
linkedNode.Color = RedBlackNodeType.Black;
}