private int CalculateOrder()
{
AugmentedTreeNode rightSubtreeRoot = FindRightSubtreeRoot();
return((Left?.NumberOfNodesInSubtree ?? 0) +
(rightSubtreeRoot?.Order ?? 0) + 1);
}
public int KthSmallest(TreeNode root, int k)
{
AugmentedTreeNode augmentedRoot = AugmentedTreeNode.CreateAugmentedTreeNode(root, null, false);
AugmentedTreeNode currentNode = augmentedRoot;
while (currentNode.Order != k)
{
currentNode = currentNode.Order > k ? currentNode.Left : currentNode.Right;
}
return(currentNode.Value);
}
public static AugmentedTreeNode CreateAugmentedTreeNode(TreeNode simpleNode, AugmentedTreeNode parentNode, bool isLeftChild)
{
if (simpleNode == null)
{
return(null);
}
AugmentedTreeNode current = new AugmentedTreeNode();
current.Parent = parentNode;
current.IsRoot = parentNode == null;
current.Value = simpleNode.val;
current.Left = CreateAugmentedTreeNode(simpleNode.left, current, true);
current.Right = CreateAugmentedTreeNode(simpleNode.right, current, false);
current.IsLeftChild = isLeftChild;
current.CalculateNodesInSubtree();
return(current);
}
private AugmentedTreeNode FindRightSubtreeRoot()
{
if (IsRoot)
{
return(null);
}
if (!IsLeftChild)
{
return(Parent);
}
AugmentedTreeNode currentParent = Parent;
while (!currentParent.IsRoot && currentParent.IsLeftChild)
{
currentParent = currentParent.Parent;
}
return(currentParent.IsRoot ? null : currentParent.Parent);
}
