/// <summary>
///Recursive function to deleteNode
///This function takes pointer to the root node. Deletes the given node.
///and then passes the pointer to the root node.
/// </summary>
/// <param name="node"></param>
/// <param name="key"></param>
/// <returns></returns>
private BinaryTreeNode DeleteNode(BinaryTreeNode node, int key)
{
//If node is null return null
if (node == null)
{
return(node);
}
/* Otherwise recursively go down the tree*/
if (key < node.GetData())
{
var child = DeleteNode(node.Left, key);
node.Left = child;
if (child != null)
{
child.Parent = node;
}
}
else if (key > node.GetData())
{
var child = DeleteNode(node.Right, key);
node.Right = child;
if (child != null)
{
child.Parent = node;
}
}
else // if node.GetData() == key, then this is the node to be deleted.
{
// if the node is leaf node.
if (node.Left == null && node.Right == null)
{
node.Parent = null;
return(null);
}
// If node having only one child.
if (node.Left == null)
{
node.Parent = null;
var rightChild = node.Right;
node.Right = null;
return(rightChild);
}
else if (node.Right == null)
{
node.Parent = null;
var leftChild = node.Left;
node.Left = null;
return(leftChild);
}
//if both left and right childs are present then,
//Either replace it with successor or with predecessor
//Here replacing it with successor
var successor = GetSuccessor(node.Right);
node.SetData(successor.GetData());
node.Right = DeleteNode(node.Right, successor.GetData());
return(node);
}
//Returning the root node after processing.
return(node);
}
public BinaryTree(BinaryTreeNode root)
{
this.Root = root;
}