private void RemoveNode(BSTNodes <T> node)
{
if (node.ChildCount == 0)
{
//remove parent pointer to us
if (node.Parent.LeftChild == node)
{
node.Parent.LeftChild = null;
}
else
{
node.Parent.RightChild = null;
}
}
else if (node.ChildCount == 1)
{
//link parent and child
var child = node.FirstChild;
child.Parent = node.Parent;
if (node.Parent.LeftChild == node)
{
node.Parent.LeftChild = child;
}
else
{
node.Parent.RightChild = child;
}
}
else if (node.ChildCount == 2)
{
//find prime node: left once, all the way right
//copy prime nodes value into temp value
//recursive delete prime node (non-recursive: make another function)
var primeNode = node.LeftChild;
while (primeNode.RightChild != null)
{
primeNode = primeNode.RightChild;
}
node.Data = primeNode.Data;
RemoveNode(primeNode);
}
}
public void Insert(T value)
{
Count++;
if (Root == null)
{
Root = new BSTNodes <T>(value);
}
else
{
BSTNodes <T> tempNode = Root;
while (tempNode != null)
{
if (value.CompareTo(tempNode.Data) < 0)
{
if (tempNode.LeftChild != null)
{
tempNode = tempNode.LeftChild;
}
else
{
//add a left child
tempNode.LeftChild = new BSTNodes <T>(value, tempNode);
break;
}
}
else if (value.CompareTo(tempNode.Data) >= 0)
{
if (tempNode.RightChild != null)
{
tempNode = tempNode.RightChild;
}
else
{
tempNode.RightChild = new BSTNodes <T>(value, tempNode);
break;
}
}
}
}
}
public bool Contains(T key)
{
BSTNodes <T> current = Root;
while (current != null)
{
if (key.CompareTo(current.Data) < 0)
{
current = current.LeftChild;
}
else if (key.CompareTo(current.Data) > 0)
{
current = current.RightChild;
}
else
{
return(true);
}
}
return(false);
}
public bool Delete(T value)
{
BSTNodes <T> tempnode = Root;
while (tempnode != null)
{
if (value.CompareTo(tempnode.Data) < 0)
{
tempnode = tempnode.LeftChild;
}
else if (value.CompareTo(tempnode.Data) > 0)
{
tempnode = tempnode.RightChild;
}
else
{
RemoveNode(tempnode);
Count--;
return(true);
}
}
return(false);
}
public BSTNodes(T data, BSTNodes <T> parent = null)
{
Data = data;
Parent = parent;
}
