CodingEasycod-g415

Subject PrimesLevel Entry–Mid~15 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Given an inclusive integer range [lo, hi] (0 <= lo <= hi <= 1e6), return how many integers v in the range have a prime number of set bits (1s) in their binary representation. For example 6 is 110 (2 set bits, prime) and 7 is 111 (3 set bits, prime). Note 1 set bit is not prime.

Implement

count_prime_set_bits(lo: int, hi: int) → int

Examples

in[6,10]out4

What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

Learn the concepts

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.