Count Pairs

Problem Overview

• Count the number of index pairs (i, j) with i < j where a[i] and a[j] have the same count of 1s in their binary form.
• Input: array of positive integers; Output: integer count of valid pairs; constraints unspecified.
• Domain: bit manipulation and binary representation within data processing.
• This coding interview problem comes from Roblox interviews and is a common interview question.