public bool Delete(int id)
{
var current = root;
var parent = root;
var isLeftChild = true;
while (current.iData != id)
{
parent = current;
if (current.iData < id)
{
isLeftChild = true;
current = current.leftChild;
}
else
{
isLeftChild = false;
current = current.rightChild;
}
if (current == null) // not in the tree
{
return(false);
}
}
// CASE 1 : LEAF NODE
if (current.leftChild == null && current.rightChild == null)
{
if (current == root)
{
root = null;
}
else if (isLeftChild)
{
parent.leftChild = null;
}
else
{
parent.rightChild = null;
}
}
else if (current.leftChild == null) // this if will execute if the node to be deleted has a right child but no left
{
// basically if the node we want to delete has a right subtree then set parent node to now equal the
// right subtree rather than the current node (which is being deleted)
if (current == root)
{
root = current.rightChild;
}
else if (isLeftChild)
{
parent.leftChild = current.rightChild;
}
else
{
parent.rightChild = current.rightChild;
}
}
else if (current.rightChild == null)
{
if (current == root)
{
root = current.leftChild;
}
else if (isLeftChild)
{
parent.leftChild = current.leftChild;
}
else
{
parent.rightChild = current.leftChild;
}
}
else // two children, so replace with inorder successor
{
var successor = GetSuccessor(current);
if (current == root)
{
root = successor;
}
else if (isLeftChild)
{
parent.leftChild = successor;
}
else
{
parent.rightChild = successor;
}
// connect successor to current's left child
successor.leftChild = current.leftChild;
}
return(true);
}