// returns -# for failure, or number of blacks to leaves
public virtual int TestIntegrityNode(RedBlackNode <KeyType, DataType> node)
{
if (node == null)
{
return(1);
}
if (node.Left != null)
{
if (node.Left.Parent != node)
{
return(-1);
}
if (node.Left.Key.CompareTo(node.Key) > 0)
{
return(-3);
}
}
if (node.Right != null)
{
if (node.Right.Parent != node)
{
return(-2);
}
if (node.Right.Key.CompareTo(node.Key) < 0)
{
return(-4);
}
}
if (node.Color == RED && ((node.Left != null && node.Left.Color == RED) || (node.Right != null && node.Right.Color == RED)))
{
return(-5);
}
// Recurse! Count the number of blacks below us
int leftCount = TestIntegrityNode(node.Left);
int rightCount = TestIntegrityNode(node.Right);
if (leftCount != rightCount)
{
return(-6);
}
return(leftCount + (node.Color == BLACK ? 1 : 0));
}
/***** Remove Operation *****/
///<summary>
/// Remove
/// removes the key and data object (delete)
///<summary>
public virtual bool Remove(KeyType key)
{
if (key == null)
{
throw(new ArgumentNullException());
}
// find node
RedBlackNode <KeyType, DataType> node = Search(key);
if (node == null)
{
return(false); // not found!
}
Delete(node);
return(true);
}
// We may have multiple, so check against object
public virtual bool Remove(KeyType key, DataType obj)
{
if (obj == null)
{
throw (new RedBlackException("RedBlackNode object is null"));
}
// find node
RedBlackNode <KeyType, DataType> node = Search(key, obj);
if (node == null)
{
// not found!
return(false);
}
Delete(node);
return(true);
}
// don't call remove-- derived classes will remove!
public virtual void ChangeSalience(DataType obj, double before, double after)
{
if (obj == null)
{
throw (new RedBlackException("ChangeSalience object is null"));
}
// find node
RedBlackNode <double, DataType> node = Search(before, obj);
if (node == null)
{
throw (new RedBlackException("ChangeSalience object not found"));
}
Delete(node);
Add(after, obj);
}
///<summary>
/// GetMaxKey
/// Returns the maximum key value
///<summary>
public KeyType GetMaxKey()
{
RedBlackNode <KeyType, DataType> treeNode = rbTree;
if (treeNode == null)
{
throw (new RedBlackException("RedBlack tree is empty"));
}
// traverse to the extreme right to find the largest key
while (treeNode.Right != null)
{
treeNode = treeNode.Right;
}
lastNodeFound = treeNode;
return(treeNode.Key);
}
///<summary>
/// RotateRight
/// Rebalance the tree by rotating the nodes to the right
///</summary>
public void RotateRight(RedBlackNode <KeyType, DataType> x)
{
// pushing node x down and to the Right to balance the tree. x's Left child (y)
// replaces x (since x < y), and y's Right child becomes x's Left child
// (since it's < x but > y).
RedBlackNode <KeyType, DataType> y = x.Left; // get x's Left node, this becomes y
// set x's Right link
x.Left = y.Right; // y's Right child becomes x's Left child
// modify parents
if (y.Right != null)
{
y.Right.Parent = x; // sets y's Right Parent to x
}
if (y != null)
{
y.Parent = x.Parent; // set y's Parent to x's Parent
}
if (x.Parent != null) // null=rbTree, could also have used rbTree
{ // determine which side of it's Parent x was on
if (x == x.Parent.Right)
{
x.Parent.Right = y; // set Right Parent to y
}
else
{
x.Parent.Left = y; // set Left Parent to y
}
}
else
{
rbTree = y; // at rbTree, set it to y
}
// link x and y
y.Right = x; // put x on y's Right
if (x != null) // set y as x's Parent
{
x.Parent = y;
}
}
public override void Deserialize(SerializationReader reader)
{
salienceSum = reader.ReadDouble(); // salienceSum = info.GetDouble("salienceSum");
// : base(info, ctxt)
intCount = reader.ReadInt32();
if (intCount != 0)
{
RedBlackNode <double, DataType>[] containers = new RedBlackNode <double, DataType> [intCount];
int ii = 0;
rbTree = DeserializeTree(reader, containers, ref ii);
for (int jj = 0; jj < intCount; jj++)
{
containers[jj].Data = (DataType)reader.ReadPointer();
}
}
else
{
rbTree = null;
}
}
public RedBlackNode <KeyType, DataType> ContainsUnderNode(DataType obj, RedBlackNode <KeyType, DataType> node)
{
if (node == null)
{
return(null);
}
if (ReferenceEquals(node.Data, obj))
{
return(node);
}
RedBlackNode <KeyType, DataType> below = ContainsUnderNode(obj, node.Left);
if (below != null)
{
return(below);
}
return(ContainsUnderNode(obj, node.Right));
}
public DataType SelectSmartItem()
{
double position;
RedBlackNode <double, DataType> result = SelectWeightedItem(smartWeight, out position);
// Adjust the weight!
// We expect an object at position to give the following
double expected = position * 2 * (salienceSum / intCount);
if (expected > result.Key)
{
// Smaller than we expected-- decrease weight!
smartWeight = (smartWeight + .25) / 2;
}
else
{
// More even than we expected-- increase weight!
smartWeight = (smartWeight + 0.5) / 2;
}
return(result.Data);
}
public DataType SelectRandomItem(RandomSearchQuality quality)
{
if (quality == RandomSearchQuality.Fast)
{
double position;
return(SelectWeightedItem(.5, out position).Data);
}
else
{
int chosen = randgen.Next(Count);
RedBlackEnumerator <double, DataType> enumerator = GetNodeEnumerator();
while (enumerator.HasMoreElements())
{
RedBlackNode <double, DataType> node = enumerator.NextElement();
if (chosen-- == 0)
{
return(node.Data);
}
}
return(default(DataType));
}
}
// Select a codelet by carefully respecting salience
public DataType SelectExactItem()
{
double salienceToGet = randgen.NextDouble() * salienceSum;
double salienceSoFar = 0;
RedBlackEnumerator <double, DataType> enumerator = GetNodeEnumerator();
while (enumerator.HasMoreElements())
{
RedBlackNode <double, DataType> node = enumerator.NextElement();
salienceSoFar += node.Key;
if (salienceSoFar >= salienceToGet)
{
return(node.Data);
}
}
// Salience calculation failure!
Console.WriteLine("WARNING: Salience miscalculation! Max is " + salienceSoFar.ToString() + " not " + salienceSum.ToString());
salienceSum = salienceSoFar;
// Try again!
return(SelectExactItem());
}
// Initialize a sentinel node (use BLACK as color)
public RedBlackNode(int color)
{
rbnLeft = rbnRight = rbnParent = null;
intColor = color;
}
public void Reset()
{
Color = 0; // red
rbnLeft = rbnRight = rbnParent = null;
// don't reset key and data-- new allocater should!
}
public RedBlackNode <KeyType, DataType> SearchRecursive(KeyType key, DataType obj, RedBlackNode <KeyType, DataType> node)
{
if (ReferenceEquals(node.Data, obj))
{
return(node);
}
if (node == null)
{
return(null);
}
// One side or the other (or both) ought to be the same key
RedBlackNode <KeyType, DataType> found = null;
if (node.Left != null)
{
if (key.CompareTo(node.Left.Key) == 0)
{
found = SearchRecursive(key, obj, node.Left);
}
else
{
// scale down the right side-- there might be more!
RedBlackNode <KeyType, DataType> below = node.Left;
while (below != null && key.CompareTo(below.Key) != 0)
{
below = below.Right;
}
if (below != null)
{
found = SearchRecursive(key, obj, below);
}
}
}
if (found == null && node.Right != null)
{
int rightResult = key.CompareTo(node.Right.Key);
if (rightResult == 0)
{
found = SearchRecursive(key, obj, node.Right);
}
else
{
// scale down the left side-- there might be more!
RedBlackNode <KeyType, DataType> below = node.Right;
while (below != null && key.CompareTo(below.Key) != 0)
{
below = below.Left;
}
if (below != null)
{
found = SearchRecursive(key, obj, below);
}
}
}
return(found);
}
public void SerializeTree(SerializationWriter writer, DataType[] elements, ref int ii, RedBlackNode <double, DataType> node)
{
if (node == null)
{
writer.Write(0.0);
}
else
{
writer.Write(node.Key);
writer.Write(node.Color == RED);
elements[ii++] = node.Data;
SerializeTree(writer, elements, ref ii, node.Left);
SerializeTree(writer, elements, ref ii, node.Right);
}
}
///<summary>
/// Clear
/// Empties or clears the tree
///<summary>
public virtual void Clear()
{
rbTree = null;
intCount = 0;
}
///<summary>
/// RestoreAfterDelete
/// Deletions from red-black trees may destroy the red-black
/// properties. Examine the tree and restore. Rotations are normally
/// required to restore it
///</summary>
private void RestoreAfterDelete(RedBlackNode <KeyType, DataType> x, RedBlackNode <KeyType, DataType> x_parent)
{
// maintain Red-Black tree balance after deleting node
RedBlackNode <KeyType, DataType> y;
while (x != rbTree && (x == null || x.Color == BLACK))
{
if (x == x_parent.Left) // determine sub tree from parent
{
y = x_parent.Right; // y is x's sibling
if (y.Color == RED)
{ // x is black, y is red - make both black and rotate
y.Color = BLACK;
x_parent.Color = RED;
RotateLeft(x_parent);
y = x_parent.Right;
}
if ((y.Left == null || y.Left.Color == BLACK) &&
(y.Right == null || y.Right.Color == BLACK))
{ // children are both black
y.Color = RED; // change parent to red
x = x_parent; // move up the tree
if (x != null)
{
x_parent = x.Parent;
}
else
{
x_parent = null;
}
}
else
{
if (y.Right == null || y.Right.Color == BLACK)
{
if (y.Left != null)
{
y.Left.Color = BLACK;
}
y.Color = RED;
RotateRight(y);
y = x_parent.Right;
}
y.Color = x_parent.Color;
x_parent.Color = BLACK;
if (y.Right != null)
{
y.Right.Color = BLACK;
}
RotateLeft(x_parent);
x = rbTree;
x_parent = null;
}
}
else
{ // right subtree - same as code above with right and left swapped
y = x_parent.Left;
if (y.Color == RED)
{
y.Color = BLACK;
x_parent.Color = RED;
RotateRight(x_parent);
y = x_parent.Left;
}
if ((y.Left == null || y.Left.Color == BLACK) &&
(y.Right == null || y.Right.Color == BLACK))
{
y.Color = RED;
x = x_parent;
if (x != null)
{
x_parent = x.Parent;
}
else
{
x_parent = null;
}
}
else
{
if (y.Left == null || y.Left.Color == BLACK)
{
if (y.Right != null)
{
y.Right.Color = BLACK;
}
y.Color = RED;
RotateLeft(y);
y = x_parent.Left;
}
y.Color = x_parent.Color;
x_parent.Color = BLACK;
if (y.Left != null)
{
y.Left.Color = BLACK;
}
RotateRight(x_parent);
x = rbTree;
x_parent = null;
}
}
}
if (x != null)
{
x.Color = BLACK;
}
}
/***** Add Operation *****/
///<summary>
/// Add
/// args: ByVal key As IComparable, ByVal data As Object
/// key is object that implements IComparable interface
/// performance tip: change to use use int type (such as the hashcode)
///</summary>
public virtual void Add(KeyType key, DataType data)
{
try
{
if (key == null || data == null)
{
throw (new RedBlackException("RedBlackNode key and data must not be null"));
}
// traverse tree - find where node belongs
int result = 0;
// create new node
RedBlackNode <KeyType, DataType> node = new RedBlackNode <KeyType, DataType>();
RedBlackNode <KeyType, DataType> temp = rbTree; // grab the rbTree node of the tree
while (temp != null)
{ // find Parent
node.Parent = temp;
result = key.CompareTo(temp.Key);
if (result == 0)
{
if (temp.Left == null || temp.Right == null)
{
break; // good enough!
}
}
if (result > 0)
{
temp = temp.Right;
}
else
{
temp = temp.Left;
}
}
// setup node
node.Key = key;
node.Data = data;
node.Left = null;
node.Right = null;
// insert node into tree starting at parent's location
if (node.Parent != null)
{
result = node.Key.CompareTo(node.Parent.Key);
if (result == 0)
{
if (node.Parent.Right == null)
{
node.Parent.Right = node;
}
else
{
node.Parent.Left = node;
}
}
else
{
if (result > 0)
{
node.Parent.Right = node;
}
else
{
node.Parent.Left = node;
}
}
}
else
{
rbTree = node; // first node added
}
RestoreAfterInsert(node); // restore red-black properities
lastNodeFound = node;
intCount = intCount + 1;
}
catch (Exception e)
{
Console.WriteLine("RedBlackTree::Add threw " + e.Message);
}
}
public RedBlackTree()
{
rbTree = null;
lastNodeFound = null;
}
public RedBlackNode <double, DataType> SelectWeightedItem(double weight, out double position)
{
if (IsEmpty())
{
position = .5;
return(null);
}
double selector = randgen.NextDouble();
// Otherwise, we have a proper tree!
double left = 0; // left possible-position
double right = 1; // right possible-position
RedBlackNode <double, DataType> node = rbTree; // current node
double expectBelow = salienceSum; // total salience below node
// Scale down tree
while (node.Left != null && node.Right != null)
{
// should we take this node?
double fraction = node.Key / expectBelow;
if (selector < fraction)
{
position = (left + right) / 2;
return(node);
}
// do we recurse on left?
if (selector < fraction + weight)
{
node = node.Left; // update node
selector -= fraction; // adjust selector from 0 to 1
selector /= weight;
right = (left + right) / 2; // adjust possible range
expectBelow *= weight; // change expected below
}
else
{
node = node.Right; // update node
selector -= fraction + weight; // adjust salience from 0 to 1
selector /= 1 - (fraction + weight);
left = (left + right) / 2; // adjust possible range
expectBelow *= (1 - weight); // change expected below
fraction = (weight + .5) / 2; // diff between left and write is less
}
}
if (node.Left == null && node.Right == null)
{
// this is a leaf-- take it!
position = (left + right) / 2;
return(node);
}
else
{
// choose between these two nodes
RedBlackNode <double, DataType> other = (node.Left == null ? node.Right : node.Left);
double nodesSum = node.Key + other.Key;
if (selector * nodesSum < node.Key)
{
position = (2 * left + right) / 3;
return(node);
}
else
{
position = (left + 2 * right) / 3;
return(other);
}
}
}
///<summary>
/// NextNode
///</summary>
public RedBlackNode <KeyType, DataType> NextElement()
{
if (stack.Count == 0)
{
throw(new RedBlackException("Element not found"));
}
// the top of stack will always have the next item
// get top of stack but don't remove it as the next nodes in sequence
// may be pushed onto the top
// the stack will be popped after all the nodes have been returned
RedBlackNode <KeyType, DataType> node = stack.Peek(); //next node in sequence
if (ascending)
{
if (node.Right == null)
{
// yes, top node is lowest node in subtree - pop node off stack
RedBlackNode <KeyType, DataType> tn = stack.Pop();
// peek at right node's parent
// get rid of it if it has already been used
while (HasMoreElements() && stack.Peek().Right == tn)
{
tn = stack.Pop();
}
}
else
{
// find the next items in the sequence
// traverse to left; find lowest and push onto stack
RedBlackNode <KeyType, DataType> tn = node.Right;
while (tn != null)
{
stack.Push(tn);
tn = tn.Left;
}
}
}
else // descending, same comments as above apply
{
if (node.Left == null)
{
// walk the tree
RedBlackNode <KeyType, DataType> tn = stack.Pop();
while (HasMoreElements() && stack.Peek().Left == tn)
{
tn = stack.Pop();
}
}
else
{
// determine next node in sequence
// traverse to left subtree and find greatest node - push onto stack
RedBlackNode <KeyType, DataType> tn = node.Left;
while (tn != null)
{
stack.Push(tn);
tn = tn.Right;
}
}
}
// the following is for .NET compatibility (see MoveNext())
Key = node.Key;
Value = node.Data;
return(node);
}
public virtual void Deserialize(SerializationReader reader)
{
intCount = reader.ReadInt32(); // intCount = info.GetInt32("intCount");
rbTree = (RedBlackNode <KeyType, DataType>)reader.ReadPointer(); // rbTree = (RedBlackNode<KeyType, DataType>)info.GetValue("rbTree", typeof(RedBlackNode<KeyType, DataType>));
lastNodeFound = null;
}
///<summary>
/// RestoreAfterInsert
/// Additions to red-black trees usually destroy the red-black
/// properties. Examine the tree and restore. Rotations are normally
/// required to restore it
///</summary>
private void RestoreAfterInsert(RedBlackNode <KeyType, DataType> x)
{
// x and y are used as variable names for brevity, in a more formal
// implementation, you should probably change the names
RedBlackNode <KeyType, DataType> y;
// maintain red-black tree properties after adding x
while (x != rbTree && x.Parent.Color == RED)
{
// Parent node is .Colored red;
if (x.Parent == x.Parent.Parent.Left) // determine traversal path
{ // is it on the Left or Right subtree?
y = x.Parent.Parent.Right; // get uncle
if (y != null && y.Color == RED)
{ // uncle is red; change x's Parent and uncle to black
x.Parent.Color = BLACK;
y.Color = BLACK;
// grandparent must be red. Why? Every red node that is not
// a leaf has only black children
x.Parent.Parent.Color = RED;
x = x.Parent.Parent; // continue loop with grandparent
}
else
{
// uncle is black; determine if x is greater than Parent
if (x == x.Parent.Right)
{ // yes, x is greater than Parent; rotate Left
// make x a Left child
x = x.Parent;
RotateLeft(x);
}
// no, x is less than Parent
x.Parent.Color = BLACK; // make Parent black
x.Parent.Parent.Color = RED; // make grandparent black
RotateRight(x.Parent.Parent); // rotate right
}
}
else
{ // x's Parent is on the Right subtree
// this code is the same as above with "Left" and "Right" swapped
y = x.Parent.Parent.Left;
if (y != null && y.Color == RED)
{
x.Parent.Color = BLACK;
y.Color = BLACK;
x.Parent.Parent.Color = RED;
x = x.Parent.Parent;
}
else
{
if (x == x.Parent.Left)
{
x = x.Parent;
RotateRight(x);
}
x.Parent.Color = BLACK;
x.Parent.Parent.Color = RED;
RotateLeft(x.Parent.Parent);
}
}
}
if (rbTree != null)
{
rbTree.Color = BLACK; // rbTree should always be black
}
}
public DataOnly(RedBlackNode <KeyType, DataType> tnode, bool ascending)
{
enumerator = new RedBlackEnumerator <KeyType, DataType>(tnode, ascending);
}
///<summary>
/// Delete
/// Delete a node from the tree and restore red black properties
///<summary>
public void Delete(RedBlackNode <KeyType, DataType> z)
{
try
{
// A node to be deleted will be:
// 1. a leaf with no children
// 2. have one child
// 3. have two children
// If the deleted node is red, the red black properties still hold.
// If the deleted node is black, the tree needs rebalancing
RedBlackNode <KeyType, DataType> x; // work node to contain the replacement node
RedBlackNode <KeyType, DataType> y; // work node
// find the replacement node (the successor to x) - the node one with
// at *most* one child.
if (z.Left == null || z.Right == null)
{
y = z; // node has sentinel as a child
}
else
{
// z has two children, find replacement node which will
// be the leftmost node greater than z
y = z.Right; // traverse right subtree
while (y.Left != null) // to find next node in sequence
{
y = y.Left;
}
}
// at this point, y contains the replacement node. it's content will be copied
// to the valules in the node to be deleted
// x (y's only child) is the node that will be linked to y's old parent.
if (y.Left != null)
{
x = y.Left;
}
else
{
x = y.Right;
}
// replace x's parent with y's parent and
// link x to proper subtree in parent
// this removes y from the chain
if (x != null)
{
x.Parent = y.Parent;
}
if (y.Parent != null)
{
if (y == y.Parent.Left)
{
y.Parent.Left = x;
}
else
{
y.Parent.Right = x;
}
}
else
{
rbTree = x; // make x the root node
}
// copy the values from y (the replacement node) to the node being deleted.
// note: this effectively deletes the node.
if (y != z)
{
z.Key = y.Key;
z.Data = y.Data;
}
if (y.Color == BLACK)
{
RestoreAfterDelete(x, y.Parent);
}
lastNodeFound = null;
intCount = intCount - 1;
}
catch (Exception e)
{
Console.WriteLine("RedBlackTree::RestoreAfterDelete threw " + e.Message);
}
}
