public RBNode(int val)
{
this.data = val;
this.color = 0;
this.left = null;
this.right = null;
this.parent = null;
}
private RBNode FindMax(RBNode rootnode)
{
if (rootnode != null)
{
while (rootnode.right != null)
{
rootnode = rootnode.right;
}
}
return(rootnode);
}
private RBNode RightRotation(RBNode node)
{
RBNode temp = node.left;
node.left = temp.right;
temp.right = node;
temp.parent = node.parent;
node.parent = temp;
if (node.left != null)
{
node.left.parent = node;
}
if (temp.parent != null)
{
temp.parent.left = temp;
}
return(temp);
}
public void LevelOrderTraversal()
{
Queue <RBNode> myQueue = new Queue <RBNode>();
myQueue.Enqueue(root);
while (myQueue.Count > 0)
{
RBNode temp = myQueue.Dequeue();
Console.Write(temp.data + " ");
if (temp.left != null)
{
myQueue.Enqueue(temp.left);
}
if (temp.right != null)
{
myQueue.Enqueue(temp.right);
}
}
}
public void InsertNode(int val)
{
RBNode temp = root;
RBNode parent = root;
while (temp != null)
{
parent = temp;
if (temp.data > val)
{
temp = temp.left;
}
else if (temp.data < val)
{
temp = temp.right;
}
else
{
return;
}
}
RBNode z = new RBNode(val);
z.parent = parent;
if (parent != null)
{
if (parent.data > val)
{
parent.left = z;
}
else
{
parent.right = z;
}
}
else
{
root = z;
root.color = 1;
}
while ((z.parent != null) && (z.color != 1) && (z.parent.color == 0))
{
if (z.parent.parent.right == z.parent)
{
if (z.parent.parent.left != null && z.parent.parent.left.color == 0)
{
z.parent.color = 1 - z.parent.color;
z.parent.parent.color = 1 - z.parent.parent.color;
z.parent.parent.left.color = 1 - z.parent.parent.left.color;
z = z.parent.parent;
}
else if (z.parent.parent.left == null || z.parent.parent.left.color == 1)
{
if (z.parent.left == z)
{
z.parent.parent.right = RightRotation(z.parent);
}
z.parent.color = 1 - z.parent.color;
z.parent.parent.color = 1 - z.parent.parent.color;
z = LeftRotation(z.parent.parent);
}
}
else
{
if (z.parent.parent.right != null && z.parent.parent.right.color == 0)
{
z.parent.color = 1 - z.parent.color;
z.parent.parent.color = 1 - z.parent.parent.color;
z.parent.parent.right.color = 1 - z.parent.parent.right.color;
z = z.parent.parent;
}
else if (z.parent.parent.right == null || z.parent.parent.right.color == 1)
{
if (z.parent.right == z)
{
z.parent.parent.left = LeftRotation(z.parent);
}
z.parent.color = 1 - z.parent.color;
z.parent.parent.color = 1 - z.parent.parent.color;
z = RightRotation(z.parent.parent);
}
}
}
while (z.parent != null)
{
z = z.parent;
}
root = z;
root.color = 1;
}
public RBTree(int data)
{
root = new RBNode(data);
root.color = 1;
}
private RBNode RemoveDoubleBlack(RBNode db, RBNode parent)
{
bool dbExist = false;
if (parent == null)
{
return(db);
}
if (parent.left == db)
{
if (parent.right == null)
{
if (parent.color == 0)
{
parent.color = 1;
}
else
{
dbExist = true;
}
db = parent;
}
else if (parent.right.color == 0)
{
SwapColors(parent, parent.right);
LeftRotation(parent);
return(RemoveDoubleBlack(db, parent));
}
else if ((parent.right.color == 1 && IsBlack(parent.right.right) && IsBlack(parent.right.left)))
{
if (parent.color == 0)
{
parent.color = 1;
}
else
{
dbExist = true;
}
parent.right.color = 0;
db = parent;
}
else if ((parent.right.color == 1 && IsBlack(parent.right.right) && IsRed(parent.right.left)))
{
SwapColors(parent.right, parent.right.left);
RightRotation(parent.right);
}
if ((parent.right.color == 1 && IsRed(parent.right.right)))
{
SwapColors(parent, parent.right);
LeftRotation(parent);
if (parent.color == 0)
{
parent.color = 1;
}
else
{
dbExist = true;
}
parent.right.right.color = 1;
db = parent;
}
}
else
{
if (parent.left == null)
{
if (parent.color == 0)
{
parent.color = 1;
}
else
{
dbExist = true;
}
db = parent;
}
else if (parent.left.color == 0)
{
SwapColors(parent, parent.left);
RightRotation(parent);
return(RemoveDoubleBlack(db, parent));
}
else if ((parent.left.color == 1 && IsBlack(parent.left.left) && IsBlack(parent.left.right)))
{
if (parent.color == 0)
{
parent.color = 1;
}
else
{
dbExist = true;
}
parent.left.color = 0;
db = parent;
}
else if ((parent.left.color == 1 && IsBlack(parent.left.left) && IsRed(parent.left.right)))
{
SwapColors(parent.left, parent.left.right);
LeftRotation(parent.left);
}
if ((parent.left.color == 1 && IsRed(parent.left.left)))
{
SwapColors(parent, parent.left);
RightRotation(parent);
if (parent.color == 0)
{
parent.color = 1;
}
else
{
dbExist = true;
}
parent.left.left.color = 1;
db = parent;
}
}
if (dbExist)
{
return(RemoveDoubleBlack(db.parent, db.parent.parent));
}
else
{
while (db.parent != null)
{
db = db.parent;
}
return(db);
}
}
private static bool IsRed(RBNode node)
{
return(node != null && node.color == 0);
}
private static bool IsBlack(RBNode node)
{
return(node == null || node.color == 1);
}
public RBNode DeleteNode(RBNode rootnode, int val)
{
bool doubleBlackExists = false;
RBNode parent = null;
if (rootnode != null)
{
if (rootnode.data == val)
{
if (rootnode.left == null || rootnode.right == null)
{
bool isLeft = true;
parent = rootnode.parent;
if (parent != null)
{
if (parent.right == rootnode)
{
isLeft = false;
}
}
if (rootnode.color == 1)
{
doubleBlackExists = true;
}
if (rootnode.left != null)
{
rootnode = rootnode.left;
rootnode.parent = parent;
}
else if (rootnode.right != null)
{
rootnode = rootnode.right;
rootnode.parent = parent;
}
else
{
rootnode = null;
}
if (parent != null)
{
if (isLeft)
{
parent.left = rootnode;
}
else
{
parent.right = rootnode;
}
}
}
else
{
RBNode temp = FindMax(rootnode.left);
rootnode.data = temp.data;
rootnode = DeleteNode(rootnode.left, temp.data);
}
}
else if (rootnode.data > val)
{
rootnode = DeleteNode(rootnode.left, val);
}
else
{
rootnode = DeleteNode(rootnode.right, val);
}
if (doubleBlackExists)
{
rootnode = RemoveDoubleBlack(rootnode, parent);
}
if (rootnode == null)
{
rootnode = parent;
}
while (rootnode.parent != null)
{
rootnode = rootnode.parent;
}
}
return(rootnode);
}
