public void Inorder(RBNode x, List <int> l, List <RBNode> n)
{
if (x.leftchild != null)
{
Inorder((RBNode)x.leftchild, l, n);
}
l.Add(x.key);
n.Add(x);
if (x.rightchild != null)
{
Inorder((RBNode)x.rightchild, l, n);
}
}
void searchBtn_Click(object sender, RoutedEventArgs e)
{
if (input.Text == "")
{
MessageBoxResult message1 = MessageBox.Show("Enter a Value!");
}
else
{
int searchItem = Convert.ToInt32(input.Text);
foundNode = (RBNode)tree.Search(tree.root, searchItem);
if (foundNode == null)
{
MessageBoxResult message1 = MessageBox.Show("Value Doesn't Exist!");
}
else
{
search = true;
}
drawStructure();
}
}
public int getBlackHeight(int searchValue)
{
// Find the Node in question
RBNode subTreeNode = (RBNode)search(searchValue);
// Note that black height starts at 0 - It should start at -1, but we compensate because this algorithm always skips the leaf
int blackHeight = 0;
// Traverse down the tree and collect the black height
while (subTreeNode.Field != null)
{
subTreeNode = (RBNode)subTreeNode.LChild;
if (subTreeNode.NodeColor == COLOR.BLACK)
{
blackHeight++;
}
}
return(blackHeight);
}
public int BlackHeight(RBNode n)
{
int sum = 0;
if (n == this.root)
{
return(0);
}
else
{
while (n != this.root)
{
if (n.color == "Black")
{
sum++;
}
n = (RBNode)n.parent;
}
return(sum);
}
}
void bhBtn_Click(object sender, RoutedEventArgs e)
{
if (input.Text == "")
{
MessageBoxResult message1 = MessageBox.Show("Enter a Height");
}
else
{
int value = Convert.ToInt32(input.Text);
RBNode bhNode = (RBNode)tree.Search((RBNode)tree.root, value);
if (bhNode == null)
{
MessageBoxResult message1 = MessageBox.Show("Node Doesn't Exist!");
}
else
{
int bh = tree.BlackHeight(bhNode);
MessageBoxResult message1 = MessageBox.Show("Black Height = " + bh.ToString());
}
drawStructure();
}
}
public void Insert(int k)
{
RBNode n = new RBNode(k);
RBNode a = root;
RBNode b = null;
while (a != null)
{
b = a;
if (n.key < a.key)
{
a = (RBNode)a.leftchild;
}
else
{
a = (RBNode)a.rightchild;
}
}
n.parent = b;
if (b == null)
{
root = n;
}
else if (n.key < b.key)
{
b.leftchild = n;
}
else if (n.key > b.key)
{
b.rightchild = n;
}
n.leftchild = null;
n.rightchild = null;
n.color = "Red";
fixUp(n);
}
// Functions to find the ancestors of nodes
public RBNode parent(RBNode N)
{
return((RBNode)N.Parent);
}
// Fix nodes
public void FixUpRB(RBTree tree, RBNode N)
{
while (parent(N).NodeColor == COLOR.RED)
{
// If parent(N) is an LChild of grandparent(N)
if (parent(N) == grandparent(N).LChild)
{
// Y is the uncle of Node N
RBNode Y = (RBNode)grandparent(N).RChild;
// Case 1: RED Uncle,
if (Y.NodeColor == COLOR.RED)
{
// Make the parent and uncle black
parent(N).NodeColor = COLOR.BLACK;
Y.NodeColor = COLOR.BLACK;
grandparent(N).NodeColor = COLOR.RED;
N = grandparent(N);
}
// Case 2: BLACK Uncle
else
{
if (N == parent(N).RChild)
{
N = parent(N);
LeftRotate(N);
}
parent(N).NodeColor = COLOR.BLACK;
grandparent(N).NodeColor = COLOR.RED;
RightRotate(grandparent(N));
}
}
else
{
// Y is the uncle of Node N
RBNode Y = (RBNode)grandparent(N).LChild;
// Case 1: RED Uncle,
if (Y.NodeColor == COLOR.RED)
{
// Make the parent and uncle black
parent(N).NodeColor = COLOR.BLACK;
Y.NodeColor = COLOR.BLACK;
grandparent(N).NodeColor = COLOR.RED;
N = grandparent(N);
}
// Case 2: BLACK Uncle
else
{
if (N == parent(N).LChild)
{
N = parent(N);
RightRotate(N);
}
parent(N).NodeColor = COLOR.BLACK;
grandparent(N).NodeColor = COLOR.RED;
LeftRotate(grandparent(N));
}
}
}
// Color it black
((RBNode)tree.root).NodeColor = COLOR.BLACK;
}
public RBNode grandparent(RBNode N)
{
return((RBNode)N.Parent.Parent);
}
public void fixUp(RBNode n)
{
RBNode parent = (RBNode)n.parent;
while (parent != null && parent.color == "Red")
{
parent = (RBNode)n.parent;
RBNode grandparent = (RBNode)n.parent.parent;
RBNode leftuncle = (RBNode)grandparent.leftchild;
RBNode rightuncle = (RBNode)grandparent.rightchild;
if (parent == leftuncle)
{
RBNode b = rightuncle;
if (b == null)
{
return;
}
else if (b.color == "Red")
{
parent.color = "Black";
b.color = "Black";
grandparent.color = "Red";
n = grandparent;
}
else if (b.color == "Black")
{
if (n == parent.rightchild)
{
n = parent;
rotateLeft(n);
}
parent.color = "Black";
grandparent.color = "Red";
rotateRight(grandparent);
}
}
else
{
RBNode b = leftuncle;
if (b == null)
{
return;
}
else if (b.color == "Red")
{
parent.color = "Black";
b.color = "Black";
grandparent.color = "Red";
n = grandparent;
}
else if (b.color == "Black")
{
if (n == n.parent.leftchild)
{
n = parent;
rotateRight(n);
}
parent.color = "Black";
grandparent.color = "Red";
rotateLeft(grandparent);
}
}
parent = (RBNode)n.parent;
}
this.root.color = "Black";
}
