Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight).

For example, the 32-bit integer ’11' has binary representation 00000000000000000000000000001011,
so the function should return 3.

Credits:

Special thanks to @ts for adding this problem and creating all test cases.

This problem can be done in log(n) time, need >> operations..

class Solution:

    # @param n, an integer

    # @return an integer

    def hammingWeight(self, n):

        res=0

        while n>0:

            res+=n&1

            n>>=1

        return res