/// <summary>
/// Insert the specified value into the tree. Runtime O(Log n)
/// </summary>
/// <param name="val">Value.</param>
public void Insert(T val)
{
m_root = zInsert(m_root, val);
}
private AVLTreeNode <T> zDeleteNode(AVLTreeNode <T> node, T val)
{
if (node == null)
{
return(node);
}
if (val.CompareTo(node.Value) > 0)
{
node.Right = zDeleteNode(node.Right, val);
}
else if (val.CompareTo(node.Value) < 0)
{
node.Left = zDeleteNode(node.Left, val);
}
else
{
//node with only one or no child
if (node.Left == null || node.Right == null)
{
AVLTreeNode <T> temp = null;
if (node.Left != null)
{
temp = node.Left;
}
else if (node.Right != null)
{
temp = node.Right;
}
node = temp;
}
else
{
//node with two children
var min = zFindMin(node.Right);
node.Value = min.Value;
//delete min since it replaced this node
node.Right = zDeleteNode(node.Right, min.Value);
}
}
//if node is null return
if (node == null)
{
return(node);
}
//update height of ancestor
node.Height = 1 + Math.Max(Height(node.Left), Height(node.Right));
//get balance factor
int balance = zGetBalanceFactor(node);
//if unbalanced then there are 4 cases to handle
if (balance > 1 && zGetBalanceFactor(node.Left) >= 0) //left left
{
return(RightRotate(node));
}
if (balance > 1 && zGetBalanceFactor(node.Left) < 0) //right right
{
node.Left = LeftRotate(node.Left);
return(RightRotate(node));
}
if (balance < -1 && zGetBalanceFactor(node.Right) <= 0) //left right
{
return(LeftRotate(node));
}
if (balance < -1 && zGetBalanceFactor(node.Right) > 0)
{
node.Right = RightRotate(node.Right);
return(LeftRotate(node));
}
return(node);
}
public AVLTree(T val)
{
m_root = new AVLTreeNode <T>(val);
}
/// <summary>
/// Delete the specified node in the tree. Runtime O(log n)
/// </summary>
/// <param name="val">Value.</param>
public void Delete(T val)
{
m_root = zDeleteNode(m_root, val);
}