Question

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.

Answer 1

Correct choice is (a) when both left, right nodes are having null pointers and only right node is null pointer respectively

Explanation: They are properties of double and single threaded binary trees respectively.