public AumentedTree(TreeNode node)
{
if (node != null)
{
this.Node = node;
Left = new AumentedTree(node.left);
Right = new AumentedTree(node.right);
Count = 1 + Left.Count + Right.Count;
}
}
private int KthSmallest(AumentedTree aumentedTree, int countPreviousSmaller)
{
if (aumentedTree == null)
{
return(0);
}
if (aumentedTree.Left.Count + countPreviousSmaller + 1 == k)
{
return(aumentedTree.Node.val);
}
if (aumentedTree.Left.Count + countPreviousSmaller >= k)
{
return(KthSmallest(aumentedTree.Left, countPreviousSmaller));
}
else
{
return(KthSmallest(aumentedTree.Right, countPreviousSmaller + aumentedTree.Left.Count + 1));
}
}