/// <summary>
/// Calculates the tree height from a specific node, recursively.
/// </summary>
/// <param name="node">Node</param>
/// <returns>Height of node's longest subtree</returns>
protected int _getTreeHeight(BSTRankedNode <T> node)
{
if (node == null || node.HasChildren == false)
{
return(0);
}
if (node.ChildrenCount == 2) // it has both a right child and a left child
{
if (node.LeftChild.SubtreeSize > node.RightChild.SubtreeSize)
{
return(1 + _getTreeHeight(node.LeftChild));
}
else
{
return(1 + _getTreeHeight(node.RightChild));
}
}
else if (node.HasLeftChild)
{
return(1 + _getTreeHeight(node.LeftChild));
}
else if (node.HasRightChild)
{
return(1 + _getTreeHeight(node.RightChild));
}
// return-functions-fix
return(0);
}
public BSTRankedNode(T value, int subtreeSize, BSTRankedNode <T> parent, BSTRankedNode <T> left, BSTRankedNode <T> right)
{
base.Value = value;
SubtreeSize = subtreeSize;
Parent = parent;
LeftChild = left;
RightChild = right;
}
/// <summary>
/// Updates the Subtree Size of a tree node.
/// Used in recusively calculating the Subtrees Sizes of nodes.
/// </summary>
/// <param name="node">BST Node.</param>
protected void _updateSubtreeSize(BSTRankedNode <T> node)
{
if (node == null)
{
return;
}
node.SubtreeSize = _subtreeSize(node.LeftChild) + _subtreeSize(node.RightChild) + 1;
_updateSubtreeSize(node.Parent);
}
/// <summary>
/// Returns the Subtrees size for a tree node if node exists; otherwise 0 (left and right nodes of leafs).
/// This is used in the recursive function UpdateSubtreeSize.
/// </summary>
/// <returns>The size.</returns>
/// <param name="node">BST Node.</param>
protected int _subtreeSize(BSTRankedNode <T> node)
{
if (node == null)
{
return(0);
}
else
{
return(node.SubtreeSize);
}
}
/// <summary>
/// Inserts an element to the tree
/// </summary>
/// <param name="item">Item to insert</param>
public override void Insert(T item)
{
var newNode = new BSTRankedNode <T>(item);
// Invoke the super BST insert node method.
// This insert node recursively starting from the root and checks for success status (related to allowDuplicates flag).
// The functions increments count on its own.
var success = base._insertNode(newNode);
if (success == false && _allowDuplicates == false)
{
throw new InvalidOperationException("Tree does not allow inserting duplicate elements.");
}
// Update the subtree-size for the newNode's parent.
_updateSubtreeSize(newNode.Parent);
}
/// <summary>
/// Remove the specified node.
/// </summary>
/// <param name="node">Node.</param>
/// <returns>>True if removed successfully; false if node wasn't found.</returns>
protected bool _remove(BSTRankedNode <T> node)
{
if (node == null)
{
return(false);
}
var parent = node.Parent;
if (node.ChildrenCount == 2) // if both children are present
{
var successor = node.RightChild;
node.Value = successor.Value;
return(true && _remove(successor));
}
else if (node.HasLeftChild) // if the node has only a LEFT child
{
base._replaceNodeInParent(node, node.LeftChild);
_updateSubtreeSize(parent);
_count--;
}
else if (node.HasRightChild) // if the node has only a RIGHT child
{
base._replaceNodeInParent(node, node.RightChild);
_updateSubtreeSize(parent);
_count--;
}
else //this node has no children
{
base._replaceNodeInParent(node, null);
_updateSubtreeSize(parent);
_count--;
}
return(true);
}
