/// <summary>
/// Goes to the next node in the tree
/// </summary>
public void Next()
{
if (currentNode.ChildRight != null)
{
currentNode = GetMinimum(currentNode.ChildRight);
return;
}
BinarySearchTreeNode <T> y = currentNode.Parent;
BinarySearchTreeNode <T> x = currentNode;
while (y != null && x == y.ChildRight)
{
x = y;
y = y.Parent;
}
currentNode = y;
}
/// <summary>
/// Goes to the previous element in the tree
/// </summary>
public void Previous()
{
if (currentNode.ChildLeft != null)
{
currentNode = GetMaximum(currentNode.ChildLeft);
return;
}
BinarySearchTreeNode <T> y = currentNode.Parent;;
BinarySearchTreeNode <T> x = currentNode;
while (y != null && x == y.ChildLeft)
{
x = y;
y = y.Parent;
}
currentNode = y;
}
/// <summary>
/// Recursively searches for a node in the tree
/// </summary>
/// <param name="el"></param>
/// <param name="root"></param>
/// <returns></returns>
private BinarySearchTreeNode <T> SearchElement_Rec(T el, BinarySearchTreeNode <T> root)
{
BinarySearchTreeNode <T> node = root;
if (node == null)
{
return(null);
}
if (el.CompareTo(node.Element) == 0)
{
return(node);
}
else if (el.CompareTo(node.Element) < 0)
{
return(SearchElement_Rec(el, node.ChildLeft));
}
else
{
return(SearchElement_Rec(el, node.ChildRight));
}
}
/// <summary>
/// Initializes a new PlebCode.Infrastructure.Collections.BinarySearchTreeIterator<T>
/// </summary>
/// <param name="root">The root node</param>
public BinarySearchTreeIterator(BinarySearchTreeNode <T> root)
{
this.currentNode = GetMinimum(root);
}
/// <summary>
/// Removes a element from the tree
/// </summary>
/// <param name="el">Element</param>
public virtual void Remove(T el)
{
BinarySearchTreeNode <T> node = SearchElement_Rec(el, root);
// Has no children
if (node.ChildLeft == null && node.ChildRight == null)
{
if (node.Parent != null)
{
if (node.Parent.ChildLeft == node)
{
node.Parent.ChildLeft = null;
}
else
{
node.Parent.ChildRight = null;
}
}
node = null;
Count -= 1;
}
// Has one child (Left)
else if (node.ChildRight == null)
{
if (node.Parent != null)
{
if (node.Parent.ChildLeft == node)
{
node.ChildLeft.Parent = node.Parent;
node.Parent.ChildLeft = node.ChildLeft;
}
else
{
node.ChildLeft.Parent = node.Parent;
node.Parent.ChildRight = node.ChildLeft;
}
}
node = null;
Count -= 1;
}
// Has one child (Right)
else if (node.ChildLeft == null)
{
if (node.Parent != null)
{
if (node.Parent.ChildRight == node)
{
node.ChildRight.Parent = node.Parent;
node.Parent.ChildRight = node.ChildRight;
}
else
{
node.ChildRight.Parent = node.Parent;
node.Parent.ChildLeft = node.ChildRight;
}
}
node = null;
Count -= 1;
}
// Has both children
else
{
BinarySearchTreeNode <T> x = node;
while (x.ChildLeft != null)
{
x = x.ChildLeft;
}
node.Element = x.Element;
BinarySearchTreeNode <T> nodeChild = x.ChildLeft == null ? x.ChildRight : x.ChildLeft;
if (x.ChildLeft != null)
{
if (x.Parent.ChildLeft == x)
{
x.Parent.ChildLeft = nodeChild;
}
else
{
x.Parent.ChildRight = nodeChild;
}
}
else
{
if (x.Parent.ChildLeft == x)
{
x.Parent.ChildLeft = nodeChild;
}
else
{
x.Parent.ChildRight = nodeChild;
}
}
Count -= 1;
}
}
/// <summary>
/// Initializes a new Binary Search Tre
/// </summary>
public BinarySearchTree()
{
root = null;
Count = 0;
}
/// <summary>
/// Empties the tree
/// </summary>
public virtual void Clear()
{
root = null;
Count = 0;
}
