Question

Using what formula can a parent node be located in an array?

(a) (i+1)/2

(b) (i-1)/2

(c) i/2

(d) 2i/2

The query is from Binary Trees in chapter Binary Trees of Data Structures & Algorithms I

This question was addressed to me during an interview for a job.

Answer 1

The correct answer is (b) (i-1)/2

Easy explanation - If a binary tree is represented in an array, parent nodes are found at indices (i-1)/2.