Question

How many randomized binary search trees can be formed by the numbers (1, 3, 2)?

(a) 2

(b) 3

(c) 6

(d) 5

The above asked question is from Binary Trees topic in section Binary Trees of Data Structures & Algorithms I

I have been asked this question in an interview for internship.

Answer 1

The correct answer is (d) 5

Easy explanation - As there are 3 numbers (1, 3, 2) so total of 6 combinations can be formed using three numbers but Since (2, 1, 3) and (2, 3, 1) are same so in total there are 5 randomized binary search tree that can be formed.