/// <summary>
/// Balances node.
/// </summary>
/// <returns>
/// The balance.
/// </returns>
public bool Balance()
{
if (this.Left != null)
{
this.Left.Balance();
}
if (this.Right != null)
{
this.Right.Balance();
}
this.UpdateHeight();
int leftHeight = 0;
int rightHeight = 0;
if (this.Left != null)
{
leftHeight = this.Left.Height;
}
if (this.Right != null)
{
rightHeight = this.Right.Height;
}
if (leftHeight - rightHeight > 1)
{
// right rotation
AVLTreeNode <T> z = this;
AVLTreeNode <T> y = this.Left;
AVLTreeNode <T> b = this.Left.Right;
bool zIsleftNode = z.Parent != null && ((AVLTreeNode <T>)z.Parent).Left == this;
z.Left = b;
if (b != null)
{
b.Parent = z;
}
y.Right = z;
if (y != null)
{
y.Parent = z.Parent;
if (y.Parent != null)
{
if (zIsleftNode)
{
((AVLTreeNode <T>)y.Parent).Left = y;
}
else
{
((AVLTreeNode <T>)y.Parent).Right = y;
}
}
}
z.Parent = y;
if (b != null)
{
b.UpdateHeight();
}
if (z != null)
{
z.UpdateHeight();
}
if (y != null)
{
y.UpdateHeight();
}
return(true);
}
if (rightHeight - leftHeight > 1)
{
// left rotation
AVLTreeNode <T> z = this;
AVLTreeNode <T> y = this.Right;
AVLTreeNode <T> b = this.Right.Left;
bool zIsleftNode = z.Parent != null && ((AVLTreeNode <T>)z.Parent).Left == this;
z.Right = b;
if (b != null)
{
b.Parent = z;
}
y.Left = z;
if (y != null)
{
y.Parent = z.Parent;
if (y.Parent != null)
{
if (zIsleftNode)
{
((AVLTreeNode <T>)y.Parent).Left = y;
}
else
{
((AVLTreeNode <T>)y.Parent).Right = y;
}
}
}
z.Parent = y;
if (b != null)
{
b.UpdateHeight();
}
if (z != null)
{
z.UpdateHeight();
}
if (y != null)
{
y.UpdateHeight();
}
return(true);
}
return(false);
}
