public void Balance(AVLNode <T> current)
{
current.FixHeight();
if (current.GetBalance() < -1)
{
if (current.Left.GetBalance() > 0)
{
RotateLeft(current.Left);
}
RotateRight(current);
}
else if (current.GetBalance() > 1)
{
//too heavy on right, rotate left
if (current.Right.GetBalance() < 0)
{
RotateRight(current.Right);
}
RotateLeft(current);
}
if (current.Parent != null)
{
Balance(current.Parent);
}
}
private AVLNode <T> RotateRight(AVLNode <T> node)
{
var parent = node.Parent;
var child = node.Left;
var cat = child.Right;
//child
child.Right = node;
child.Parent = parent;
//node stuff
node.Left = cat;
node.Parent = child;
if (node == root)
{
root = child;
}
//cat stuff
if (cat != null)
{
cat.Parent = node;
}
//parent stuff
if (parent != null)
{
if (parent.Left == node)
{
parent.Left = child;
}
else
{
parent.Right = child;
}
}
node.FixHeight();
child.FixHeight();
return(child);
}
private AVLNode <T> RotateLeft(AVLNode <T> node)
{
var parent = node.Parent;
var child = node.Right;
var childleft = child.Left;
//Node
node.Right = childleft;
node.Parent = child;
//Child
child.Left = node;
child.Parent = parent;
if (node == root)
{
root = child;
}
//Possible GChild
if (childleft != null)
{
childleft.Parent = node;
}
//Possible Parent
if (parent != null)
{
if (parent.Right == node)
{
parent.Right = child;
}
else
{
parent.Left = child;
}
}
node.FixHeight();
child.FixHeight();
return(child);
}
