public AvlNode <TKey, TValue> AddOrReplace([NotNull] TKey key, TValue value)
{
var compare = key.CompareTo(this.key);
if (compare == 0)
{
this.value = value;
return(this);
}
if (compare < 0)
{
if (this.left != null)
{
this.left = this.left.AddOrReplace(key, value);
// Check whether rebalance is necessary and update height
var node = Rebalance(this);
node.height = CalculateHeight(node);
return(node);
}
else
{
this.left = new AvlNode <TKey, TValue>(key, value);
this.height = 2;
return(this);
}
}
else
{
if (this.right != null)
{
this.right = this.right.AddOrReplace(key, value);
var node = Rebalance(this);
node.height = CalculateHeight(node);
return(node);
}
else
{
this.right = new AvlNode <TKey, TValue>(key, value);
this.height = 2;
return(this);
}
}
}
private static AvlNode <TKey, TValue> RightLeftRotation(AvlNode <TKey, TValue> avlNode)
{
avlNode.right = RightRotation(avlNode.right);
return(LeftRotation(avlNode));
}
private static AvlNode <TKey, TValue> LeftRightRotation(AvlNode <TKey, TValue> avlNode)
{
avlNode.left = LeftRotation(avlNode.left);
return(RightRotation(avlNode));
}
private static int CalculateHeight(AvlNode <TKey, TValue> avlNode)
{
return(Math.Max(Height(avlNode.left), Height(avlNode.right)) + 1);
}
public bool Remove([NotNull] TKey key, out AvlNode <TKey, TValue> node)
{
var compare = key.CompareTo(this.key);
if (compare == 0)
{
if (this.left == null)
{
node = this.right;
}
else
{
if (this.right == null)
{
node = this.left;
}
else
{
var top = MinValueNode(this.right);
this.right.Remove(top.key, out top);
top.left = this.left;
top.right = this.right;
top = Rebalance(top);
top.height = CalculateHeight(top);
node = top;
}
}
return(true);
}
if (compare < 0)
{
if (this.left != null)
{
var result = this.left.Remove(key, out node);
if (result)
{
this.left = node;
node = Rebalance(this);
node.height = CalculateHeight(node);
}
return(result);
}
node = this;
return(false);
}
if (this.right != null)
{
var result = this.right.Remove(key, out node);
if (result)
{
this.right = node;
node = Rebalance(this);
node.height = CalculateHeight(node);
}
return(result);
}
node = this;
return(false);
}
