What are double and single threaded trees?
(a) when both left, right nodes are having null pointers and only right node is null pointer respectively
(b) having 2 and 1 node
(c) using single and double linked lists
(d) using heaps and priority queues
Origin of the question is Threaded Binary Tree in section Binary Trees of Data Structures & Algorithms I
This question was posed to me in a national level competition.