Problem Statement

You are part of the Cyber Security team in your company, working on a decryption algorithm that transforms a number into the count of set bits (1s) in its binary representation. This process can be repeated multiple times, and each time the number is replaced by the number of set bits in its binary form. A number is considered a possible decryption if it can be reduced to 1 after applying this dec ryption algorithm exactly K times — that is, after the Kth step, the result becomes 1. For example, applying the algorithm once to the number 12 (binary 1100) gives 2 because it has two set bits. Applying it again to 2 (binary 10) gives 1, so 12 becomes 1 after two steps. You are given a binary string N representing a number and an integer K. You need to determine the number of integers less than or equal to N (in binary) that can be transformed into 1 after exactly K decryption steps. Since the an swer can be very large, return the result modulo 10 9 + 7. Function Description Complete the De