/// <summary>
/// Used by AddTree before reinsertion of the node
/// </summary>
internal virtual void ClearRelations()
{
mColor = RBTreeColor.Black;
mLeft = null;
mRight = null;
mParent = null;
}
///<summary>
///Return a pointer to the largest key smaller than x
///
protected RBTreeNodeBase <T, P> Predecessor(RBTreeNodeBase <T, P> x)
{
RBTreeNodeBase <T, P> y;
if (x.mLeft != null)
{
// If left is not NULL then go left one and
// then keep going right until we find a node with
// no right pointer.
for (y = x.mLeft; y.mRight != null; y = y.mRight)
{
;
}
}
else
{
// Go up the tree until we get to a node that is on the
// right of its parent (or the root) and then return the
// parent.
y = x.mParent;
while (y != null && x == y.mLeft)
{
x = y;
y = y.mParent;
}
}
return(y);
}
///<summary>
///Tree constructor
///</summary>
public RBTreeBase(bool unique)
{
mRoot = null;
mComparer = Comparer <T> .Default;
mCount = 0;
mUnique = unique;
}
///<summary>
///Tree constructor with comparer
///</summary>
public RBTreeBase(IComparer <T> aComparer, bool unique)
{
mRoot = null;
mComparer = aComparer;
mCount = 0;
mUnique = unique;
}
/// <summary>
/// This method was added by Dmitriano. Re-adds root element to the three
/// after Comparer has been changed.
/// </summary>
/// <param name="node"></param>
void AddTree(RBTreeNodeBase <T, P> node)
{
if (node != null)
{
AddTree(node.Left);
RBTreeNodeBase <T, P> right = node.Right;
//reuse this node to avoid superfluous dynamic memory allocation
node.ClearRelations();
RBTreeNodeBase <T, P> result;
bool insert = true;
result = Traverse(ref insert, node.Key, node);
Debug.Assert(result == node);
if (!insert)
{
throw new System.InvalidOperationException("A node alredy exists in the destination tree.");
}
mCount++;
AddTree(right);
}
}
///<summary>
///Copy from other node
///</summary>
internal virtual void CopyFrom(RBTreeNodeBase <T, P> z)
{
if (z.mLeft != null)
{
z.mLeft.mParent = this;
}
this.mLeft = z.mLeft;
if (z.mRight != null)
{
z.mRight.mParent = this;
}
this.mRight = z.mRight;
//2) replace z with this in the parent node
if (z.mParent != null)
{
if (z.mParent.mLeft == z)
{
z.mParent.SetLeft(this);
}
else
{
z.mParent.SetRight(this);
}
}
this.mColor = z.mColor;
this.SetParent(z.mParent);
}
///<summary>
///Set parent node
///</summary>
internal override void SetParent(RBTreeNodeBase <T, RBOrderedNodeParam> value)
{
mParent = value;
if (mParent != null)
{
mParent.OnUpdateCount();
}
}
public int IndexOfKey(T key)
{
RBTreeNodeBase <T, RBOrderedNodeParam> node = Find(key);
if (node == null)
{
return(-1);
}
return(GetOrder(node as RBOrderedTreeNode <T>));
}
///<summary>
/// Rotate our tree Right
///
/// X Y
/// / \ / \
/// A Y <---rb_right_rotate(Y) X C
/// / \ / \
/// B C A B
///
/// N.B. This does not change the ordering.
///
/// We assume that neither X or Y is NULL
///<summary>
protected void RightRotate(RBTreeNodeBase <T, P> y)
{
RBTreeNodeBase <T, P> x;
// set X
x = y.mLeft;
// Turn X's right subtree into Y's left subtree (move B)
y.mLeft = x.mRight;
// If B is not null, set it's parent to be Y
if (x.mRight != null)
{
x.mRight.mParent = y;
}
// Set X's parent to be what Y's parent was
x.mParent = y.mParent;
// if Y was the root
if (y.mParent == null)
{
mRoot = x;
}
else
{
// Set Y's parent's left or right pointer to be X
if (y == y.mParent.mLeft)
{
y.mParent.mLeft = x;
}
else
{
y.mParent.mRight = x;
}
}
// Put Y on X's right
x.mRight = y;
// Set Y's parent to be X
y.mParent = x;
y.OnUpdateCount();
}
///<summary>
/// Rotate our tree Left
///
/// X rb_left_rotate(X)---> Y
/// / \ / \
/// A Y X C
/// / \ / \
/// B C A B
///
/// N.B. This does not change the ordering.
///
/// We assume that neither X or Y is NULL
///<summary>
protected void LeftRotate(RBTreeNodeBase <T, P> x)
{
RBTreeNodeBase <T, P> y;
// set Y
y = x.mRight;
// Turn Y's left subtree into X's right subtree (move B)
x.mRight = y.mLeft;
// If B is not null, set it's parent to be X
if (y.mLeft != null)
{
y.mLeft.mParent = x;
}
// Set Y's parent to be what X's parent was
y.mParent = x.mParent;
// if X was the root
if (x.mParent == null)
{
mRoot = y;
}
else
{
// Set X's parent's left or right pointer to be Y
if (x == x.mParent.mLeft)
{
x.mParent.mLeft = y;
}
else
{
x.mParent.mRight = y;
}
}
// Put X on Y's left
y.mLeft = x;
// Set X's parent to be Y
x.mParent = y;
x.OnUpdateCount();
}
/// <summary>
/// This method was added by Dmitriano. Re-adds removed node
/// with cleared relations to the tree.
/// </summary>
/// <param name="node">A tree node previously deleted by Remove.</param>
public void Add(ITreeNode <T> node)
{
RBTreeNodeBase <T, P> t_node = node as RBTreeNodeBase <T, P>;
t_node.CheckRelationsCleared();
bool insert = true;
RBTreeNodeBase <T, P> key = Traverse(ref insert, t_node.Key, t_node);
Debug.Assert(key == node);
if (!insert)
{
throw new InvalidOperationException("Node already exists.");
}
mCount++;
}
///<summary>
///Get order index of item
///This operation is O(logN) operation
///</summary>
public int GetOrder(RBOrderedTreeNode <T> aItem)
{
RBTreeNodeBase <T, RBOrderedNodeParam> node = aItem;
int idx = node.mParam.mRank;
while (true)
{
if (node.mParent == null)
{
break;
}
if (node.mParent.mRight == node)
{
idx += node.mParent.mParam.mRank;
}
node = node.mParent;
}
return(idx - 1);
}
///<summary>
///Get item by order index
///This operation is O(logN) operation
///</summary>
public RBOrderedTreeNode <T> GetByOrder(int idx)
{
int m = idx + 1;
RBTreeNodeBase <T, RBOrderedNodeParam> node = mRoot;
while (node != null && m > 0)
{
if (m < node.mParam.mRank)
{
node = node.mLeft;
}
else if (m > node.mParam.mRank)
{
m = m - node.mParam.mRank;
node = node.mRight;
}
else if (m == node.mParam.mRank)
{
return(node as RBOrderedTreeNode <T>);
}
}
return(null);
}
///<summary>
///Set right node
///</summary>
internal override void SetRight(RBTreeNodeBase <T, RBOrderedNodeParam> value)
{
mRight = value;
OnUpdateCount();
}
///<summary>
///Go trough tree and find the node by the key.
///Might add new node if node doesn't exist.
///node_to_reuse parameter added by Dmitriano to avoid superfluous dynamic memory allocation
///if node_to_reuse is not null aKey should be equal to node_to_reuse.Key
///</summary>
internal RBTreeNodeBase <T, P> Traverse(ref bool aInsert, T aKey, RBTreeNodeBase <T, P> node_to_reuse = null)
{
RBTreeNodeBase <T, P> x, y, z;
int cmp;
//walk down the tree
y = null;
x = mRoot;
while (x != null)
{
y = x;
cmp = mComparer.Compare(aKey, x.mKey);
if (!mUnique && cmp == 0 && aInsert == true)
{
cmp = 1;
}
if (cmp < 0)
{
x = x.mLeft;
}
else if (cmp > 0)
{
x = x.mRight;
}
else
{
aInsert = false;
return(x);
}
}
//x is null. return null if node must not be inserted
if (!aInsert)
{
return(null);
}
if (node_to_reuse != null) //this condition was changed by Dmitriano
{
z = node_to_reuse; //ignore aKey parameter here
}
else
{
z = NewNode();
z.mKey = aKey;
}
//x is null and insert operation is requested
//create new node
z.mParent = y;
if (y == null)
{
mRoot = z;
}
else
{
cmp = mComparer.Compare(z.mKey, y.mKey);
if (cmp == 0)
{
cmp = 1;
}
if (cmp < 0)
{
y.SetLeft(z);
}
else
{
y.SetRight(z);
}
}
z.mColor = RBTreeColor.Red;
Balance(z);
mRoot.mColor = RBTreeColor.Black;
return(z);
}
///<summary>
///Balance tree past inserting
///</summary>
protected void Balance(RBTreeNodeBase <T, P> z)
{
RBTreeNodeBase <T, P> x, y;
//Having added a red node, we must now walk back up the tree balancing
//it, by a series of rotations and changing of colours
x = z;
//While we are not at the top and our parent node is red
//N.B. Since the root node is garanteed black, then we
//are also going to stop if we are the child of the root
while (x != mRoot && (x.mParent.mColor == RBTreeColor.Red))
{
//if our parent is on the left side of our grandparent
if (x.mParent == x.mParent.mParent.mLeft)
{
//get the right side of our grandparent (uncle?)
y = x.mParent.mParent.mRight;
if (y != null && y.mColor == RBTreeColor.Red)
{
//make our parent black
x.mParent.mColor = RBTreeColor.Black;
//make our uncle black
y.mColor = RBTreeColor.Black;
//make our grandparent red
x.mParent.mParent.mColor = RBTreeColor.Red;
//now consider our grandparent
x = x.mParent.mParent;
}
else
{
//if we are on the right side of our parent
if (x == x.mParent.mRight)
{
//Move up to our parent
x = x.mParent;
LeftRotate(x);
}
/* make our parent black */
x.mParent.mColor = RBTreeColor.Black;
/* make our grandparent red */
x.mParent.mParent.mColor = RBTreeColor.Red;
/* right rotate our grandparent */
RightRotate(x.mParent.mParent);
}
}
else
{
//everything here is the same as above, but
//exchanging left for right
y = x.mParent.mParent.mLeft;
if (y != null && y.mColor == RBTreeColor.Red)
{
x.mParent.mColor = RBTreeColor.Black;
y.mColor = RBTreeColor.Black;
x.mParent.mParent.mColor = RBTreeColor.Red;
x = x.mParent.mParent;
}
else
{
if (x == x.mParent.mLeft)
{
x = x.mParent;
RightRotate(x);
}
x.mParent.mColor = RBTreeColor.Black;
x.mParent.mParent.mColor = RBTreeColor.Red;
LeftRotate(x.mParent.mParent);
}
}
}
mRoot.mColor = RBTreeColor.Black;
}
///<summary>
///Remove all items
///</summary>
public void Clear()
{
mRoot = null;
mCount = 0;
}
///<summary>
///Set parent node
///</summary>
internal virtual void SetParent(RBTreeNodeBase <T, P> value)
{
mParent = value;
}
///<summary>
///Set left node
///</summary>
internal virtual void SetLeft(RBTreeNodeBase <T, P> value)
{
mLeft = value;
}
///<summary>
///Set right node
///</summary>
internal virtual void SetRight(RBTreeNodeBase <T, P> value)
{
mRight = value;
}
///<summary>
///Copy from other node
///</summary>
internal override void CopyFrom(RBTreeNodeBase <T, RBOrderedNodeParam> z)
{
this.mParam.mRank = z.mParam.mRank;
this.mParam.mCount = z.mParam.mCount;
base.CopyFrom(z);
}
/// <summary>
/// Delete the node z, and free up the space
/// </summary>
protected virtual void Delete(RBTreeNodeBase <T, P> z)
{
RBTreeNodeBase <T, P> x, y;
if (z.mLeft == null || z.mRight == null)
{
y = z;
}
else
{
y = Successor(z);
}
if (y.mLeft != null)
{
x = y.mLeft;
}
else
{
x = y.mRight;
}
if (x != null)
{
x.SetParent(y.mParent);
}
if (y.mParent == null)
{
mRoot = x;
}
else
{
if (y == y.mParent.mLeft)
{
y.mParent.SetLeft(x);
}
else
{
y.mParent.SetRight(x);
}
}
if (y != z)
{
//we must replace 'z' with 'y' node
y.CopyFrom(z);
if (z == mRoot)
{
mRoot = y;
}
//we do this all above instead of the following line in original code
//to provide guarantee of the persistence of the node in the tree
//z.mKey = y.mKey;
}
if (y.mColor == RBTreeColor.Black && x != null)
{
DeleteFix(x);
}
}
/// <summary>
/// Restore the reb-black properties after a delete
/// </summary>
/// <param name="x"></param>
protected void DeleteFix(RBTreeNodeBase <T, P> x)
{
RBTreeNodeBase <T, P> w;
while (x != mRoot && x.mColor == RBTreeColor.Black)
{
if (x == x.mParent.mLeft)
{
w = x.mParent.mRight;
if (w == null)
{
x = x.mParent;
continue;
}
if (w.mColor == RBTreeColor.Red)
{
w.mColor = RBTreeColor.Black;
x.mParent.mColor = RBTreeColor.Red;
LeftRotate(x.mParent);
w = x.mParent.mRight;
}
if (w == null)
{
x = x.mParent;
continue;
}
if ((w.mLeft == null || w.mLeft.mColor == RBTreeColor.Black) &&
(w.mRight == null || w.mRight.mColor == RBTreeColor.Black))
{
w.mColor = RBTreeColor.Red;
x = x.mParent;
}
else
{
if (w.mRight == null || w.mRight.mColor == RBTreeColor.Black)
{
if (w.mLeft != null)
{
w.mLeft.mColor = RBTreeColor.Black;
}
w.mColor = RBTreeColor.Red;
RightRotate(w);
w = x.mParent.mRight;
}
w.mColor = x.mParent.mColor;
x.mParent.mColor = RBTreeColor.Black;
if (w.mRight != null)
{
w.mRight.mColor = RBTreeColor.Black;
}
LeftRotate(x.mParent);
x = mRoot;
}
}
else
{
w = x.mParent.mLeft;
if (w == null)
{
x = x.mParent;
continue;
}
if (w.mColor == RBTreeColor.Red)
{
w.mColor = RBTreeColor.Black;
x.mParent.mColor = RBTreeColor.Red;
RightRotate(x.mParent);
w = x.mParent.mLeft;
}
if (w == null)
{
x = x.mParent;
continue;
}
if ((w.mRight == null || w.mRight.mColor == RBTreeColor.Black) &&
(w.mLeft == null || w.mLeft.mColor == RBTreeColor.Black))
{
w.mColor = RBTreeColor.Red;
x = x.mParent;
}
else
{
if (w.mLeft == null || w.mLeft.mColor == RBTreeColor.Black)
{
if (w.mRight != null)
{
w.mRight.mColor = RBTreeColor.Black;
}
w.mColor = RBTreeColor.Red;
LeftRotate(w);
w = x.mParent.mLeft;
}
w.mColor = x.mParent.mColor;
x.mParent.mColor = RBTreeColor.Black;
if (w.mLeft != null)
{
w.mLeft.mColor = RBTreeColor.Black;
}
RightRotate(x.mParent);
x = mRoot;
}
}
}
x.mColor = RBTreeColor.Black;
}
