private AvlTreeNode <T> Balance()
{
FixHeight();
var balanceFactor = BalanceFactor();
if (balanceFactor == 2)
{
if (Right !.BalanceFactor() < 0)
{
Right = Right.RotateRight();
}
return(RotateLeft());
}
if (balanceFactor == -2)
{
if (Left !.BalanceFactor() > 0)
{
Left = Left.RotateLeft();
}
return(RotateRight());
}
return(this);
}
internal static AvlTreeNode <T>?Remove(AvlTreeNode <T>?root, T key, IComparer <T> comparer, int deep)
{
if (root == null)
{
return(null);
}
if (comparer.Compare(key, root.Value) < 0)
{
root.Left = Remove(root.Left, key, comparer, deep + 1);
}
else if (comparer.Compare(key, root.Value) > 0)
{
root.Right = Remove(root.Right, key, comparer, deep + 1);
}
else
{
var beforeLeft = root.Left;
var beforeRight = root.Right;
if (beforeRight == null)
{
return(beforeLeft);
}
var min = beforeRight.Min();
min.Right = beforeRight.RemoveMin();
min.Left = beforeLeft;
return(min.Balance());
}
return(root.Balance());
}
internal static AvlTreeNode <T> Add(AvlTreeNode <T>?root, T key, IComparer <T> comparer)
{
if (root == null)
{
return(new AvlTreeNode <T>(key));
}
var compare = comparer.Compare(key, root.Value);
if (compare < 0)
{
root.Left = Add(root.Left, key, comparer);
}
else if (compare > 0)
{
root.Right = Add(root.Right, key, comparer);
}
else
{
throw new InvalidOperationException("Key exists");
}
return(root.Balance());
}
public void Remove(T key)
{
Root = AvlTreeNode <T> .Remove(Root, key, Comparer, 0);
}
public void Add(T key)
{
Root = AvlTreeNode <T> .Add(Root, key, Comparer);
}