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

Example

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

Solution

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class Solution(object):
    def hammingWeight(self, n):
        """
        :type n: int
        :rtype: int
        """

        ret = 0
        while n != 0:
            if n % 2 == 1:
                ret += 1
            n = n/2
        return ret