3519. Count Numbers with Non-Decreasing Digits

You are given two integers, l and r, represented as strings, and an integer b. Return the count of integers in the inclusive range [l, r] whose digits are in non-decreasing order when represented in base b. An integer is considered to have non-decreasing digits if, when read from left to right (from the most significant digit to the least significant digit), each digit is greater than or equal to