protected void DeleteNode(BinaryKeyValueNode <Tkey, Tvalue> node)
{
if (node == null)
{
throw new ArgumentNullException();
}
if (node.LeftChild != null && node.RightChild != null) //2 childs
{
BinaryKeyValueNode <Tkey, Tvalue> replaceBy = random.NextDouble() > .5 ? InOrderSuccesor(node) : InOrderPredecessor(node);
DeleteNode(replaceBy);
node.Value = replaceBy.Value;
node.Key = replaceBy.Key;
}
else //1 or less childs
{
var child = node.LeftChild == null ? node.RightChild : node.LeftChild;
if (node.Parent.RightChild == node)
{
node.Parent.RightChild = child;
}
else
{
node.Parent.LeftChild = child;
}
}
Count--;
}
public void Insert(Tkey key, Tvalue value)
{
BinaryKeyValueNode <Tkey, Tvalue> parent = null;
BinaryKeyValueNode <Tkey, Tvalue> current = Root;
int compare = 0;
while (current != null)
{
parent = current;
compare = current.Key.CompareTo(key);
current = compare < 0 ? current.RightChild : current.LeftChild;
}
BinaryKeyValueNode <Tkey, Tvalue> newNode = new BinaryKeyValueNode <Tkey, Tvalue>(key, value);
if (parent != null)
{
if (compare < 0)
{
parent.RightChild = newNode;
}
else
{
parent.LeftChild = newNode;
}
}
else
{
Root = newNode;
}
newNode.Parent = parent;
Count++;
}
protected BinaryKeyValueNode <Tkey, Tvalue> FindNode(Tkey key, bool ExceptionIfKeyNotFound = true)
{
BinaryKeyValueNode <Tkey, Tvalue> current = Root;
while (current != null)
{
int compare = current.Key.CompareTo(key);
if (compare == 0)
{
return(current);
}
if (compare < 0)
{
current = current.RightChild;
}
else
{
current = current.LeftChild;
}
}
if (ExceptionIfKeyNotFound)
{
throw new KeyNotFoundException();
}
else
{
return(null);
}
}
protected BinaryKeyValueNode <Tkey, Tvalue> InOrderPredecessor(BinaryKeyValueNode <Tkey, Tvalue> node)
{
BinaryKeyValueNode <Tkey, Tvalue> succesor = node.LeftChild;
while (succesor.RightChild != null)
{
succesor = succesor.RightChild;
}
return(succesor);
}
private BinaryKeyValueNode <Tkey> InOrderPredecessor(BinaryKeyValueNode <Tkey> node)
{
BinaryKeyValueNode <Tkey> succesor = node.LeftChild;
while (succesor.RightChild != null)
{
succesor = succesor.RightChild;
}
return(succesor);
}
private BinaryKeyValueNode <Tkey> FindNode(Tkey key, bool ExceptionIfKeyNotFound = true)
{
BinaryKeyValueNode <Tkey> current = Root;
while (current != null)
{
int compare = current.Key.CompareTo(key);
if (compare == 0)
{
return(current);
}
if (compare < 0)
{
current = current.RightChild;
}
else
{
current = current.LeftChild;
}
}
return(null);
}
protected IEnumerable <Tvalue> TraverseNode(BinaryKeyValueNode <Tkey, Tvalue> node, DepthFirstTraversalMethod method)
{
IEnumerable <Tvalue> TraverseLeft = node.LeftChild == null ? new Tvalue[0] : TraverseNode(node.LeftChild, method),
TraverseRight = node.RightChild == null ? new Tvalue[0] : TraverseNode(node.RightChild, method),
Self = new Tvalue[1] {
node.Value
};
switch (method)
{
case DepthFirstTraversalMethod.PreOrder:
return(Self.Concat(TraverseLeft).Concat(TraverseRight));
case DepthFirstTraversalMethod.InOrder:
return(TraverseLeft.Concat(Self).Concat(TraverseRight));
case DepthFirstTraversalMethod.PostOrder:
return(TraverseLeft.Concat(TraverseRight).Concat(Self));
default:
throw new ArgumentException();
}
}
/// <summary>
/// Finds and deletes an element.
/// </summary>
/// <param name="node">Key to be deleted </param>
/// <returns>void<Tkey></returns>
public void DeleteKey(Tkey key)
{
BinaryKeyValueNode <Tkey> node = FindNode(key);
DeleteNode(node);
}
