Number of 1 Bits

The problem Given a positive integer n, write a function that returns the number of set bits in its binary representation (also known as the Hamming weight). A set bit refers to a bit in the binary representation of a number that has a value of 1. Examples Input: n = 11 Output: 3 Explanation: The input binary string 1011 has a total of three set bits. Input: n = 128 Output: 1 Explanation: The input binary string 10000000 has a total of one set bit. Input: n = 2147483645 Output: 30 Explanation: The input binary string 1111111111111111111111111111101 has a total of thirty set bits. Constraints 1 <= n <= 2^31 - 1 Follow up: If this function is called many times, how would you optimize it? ...