191. Number of 1 Bits

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

Example 1:

Input: 11
Output: 3
Explanation: Integer 11 has binary representation 00000000000000000000000000001011 

Example 2:

Input: 128
Output: 1
Explanation: Integer 128 has binary representation 00000000000000000000000010000000

Python

 
class Solution(object):
    def hammingWeight(self, n):
        """
        :type n: int
        :rtype: int
        """
        a = str(bin(n)).replace("b", "")
        result = 0
        for i in a:
            result += int(i)
        return result