You are given a number n and digit d (d <= n <= 10). Your goal is to count all d-digit numbers including 0 to n that are divisible by 3.

The question was asked to me in a company interview and the only logic I gave was from backtracking by rearranging the digits and excluding the case where the left-most number is 0, but the interviewer didn't look much happy with my logic. Is there any better logic for these types of questions in general?

Thanks in advance.