private MyAVLNode Find(int target, MyAVLNode current)
{
if (target < current.Data)
{
if (target == current.Data)
{
return(current);
}
else
{
return(Find(target, current.leftChild));
}
}
else
{
if (target == current.Data)
{
return(current);
}
else
{
return(Find(target, current.rightChild));
}
}
}
private MyAVLNode balance_tree(MyAVLNode current)
{
int b_factor = balance_factor(current);
if (b_factor > 1)
{
if (balance_factor(current.leftChild) > 0)
{
current = RotateLL(current);
}
else
{
current = RotateLR(current);
}
}
else if (b_factor < -1)
{
if (balance_factor(current.rightChild) > 0)
{
current = RotateRL(current);
}
else
{
current = RotateRR(current);
}
}
return(current);
}
private MyAVLNode RotateRL(MyAVLNode parent)
{
MyAVLNode pivot = parent.rightChild;
parent.rightChild = RotateLL(pivot);
return(RotateRR(parent));
}
private MyAVLNode RotateLL(MyAVLNode parent)
{
MyAVLNode pivot = parent.leftChild;
parent.leftChild = pivot.rightChild;
pivot.rightChild = parent;
return(pivot);
}
private int balance_factor(MyAVLNode current)
{
int l = getHeight(current.leftChild);
int r = getHeight(current.rightChild);
int b_factor = l - r;
return(b_factor);
}
private void PostOrderDisplayTree(MyAVLNode current)
{
if (current != null)
{
PostOrderDisplayTree(current.leftChild);
PostOrderDisplayTree(current.rightChild);
Console.Write("{0} ", current.Data);
}
}
public void Add(int data)
{
MyAVLNode newItem = new MyAVLNode(data);
if (root == null)
{
root = newItem;
}
else
{
root = RecursiveInsert(root, newItem);
}
}
private int getHeight(MyAVLNode current)
{
int height = 0;
if (current != null)
{
int l = getHeight(current.leftChild);
int r = getHeight(current.rightChild);
int m = max(l, r);
height = m + 1;
}
return(height);
}
private MyAVLNode RecursiveInsert(MyAVLNode current, MyAVLNode n)
{
if (current == null)
{
current = n;
return(current);
}
else if (n.Data < current.Data)
{
current.leftChild = RecursiveInsert(current.leftChild, n);
current = balance_tree(current);
}
else if (n.Data > current.Data)
{
current.rightChild = RecursiveInsert(current.rightChild, n);
current = balance_tree(current);
}
return(current);
}
private MyAVLNode RemoveX(MyAVLNode current, int target)
{
MyAVLNode parent;
if (current == null)
{
return(null);
}
else
{
//left subtree
if (target < current.Data)
{
current.leftChild = RemoveX(current.leftChild, target);
if (balance_factor(current) == -2)//here
{
if (balance_factor(current.rightChild) <= 0)
{
current = RotateRR(current);
}
else
{
current = RotateRL(current);
}
}
}
//right subtree
else if (target > current.Data)
{
current.rightChild = RemoveX(current.rightChild, target);
if (balance_factor(current) == 2)
{
if (balance_factor(current.leftChild) >= 0)
{
current = RotateLL(current);
}
else
{
current = RotateLR(current);
}
}
}
//if target is found
else
{
if (current.rightChild != null)
{
//delete its inorder successor
parent = current.rightChild;
while (parent.leftChild != null)
{
parent = parent.leftChild;
}
current.Data = parent.Data;
current.rightChild = RemoveX(current.rightChild, parent.Data);
if (balance_factor(current) == 2)//rebalancing
{
if (balance_factor(current.leftChild) >= 0)
{
current = RotateLL(current);
}
else
{
current = RotateLR(current);
}
}
}
else
{ //if current.left != null
return(current.leftChild);
}
}
}
return(current);
}
public void RemoveX(int target)
{
root = RemoveX(root, target);
}