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).

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



class Solution:
    # @param n, an integer
    # @return an integer
    def hammingWeight(self, n):
        return bin(n).count('1')


600 / 600 test cases passed.
Status: Accepted
Runtime: 45 ms

一共有600个test case难怪这么慢,最终还是通过了~!