Leetcode: Number of Bits

最新推荐文章于 2022-07-07 00:00:00 发布

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最新推荐文章于 2022-07-07 00:00:00 发布

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本文介绍了如何通过Python编写函数来计算一个无符号整数中1的位数，并讨论了两种不同的实现方式及其性能比较。通过实例演示了哈明重量的概念与应用。

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Question

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.

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Solution1

class Solution(object):
    def hammingWeight(self, n):
        """
        :type n: int
        :rtype: int
        """
        res = 0

        while n!=0:
            if n%2==1:
                res += 1
            n = n >> 1

        return res

Solution2

The code below is faster. The number of loop is equal to number of bit 1.
refer tt here

class Solution(object):
    def hammingWeight(self, n):
        """
        :type n: int
        :rtype: int
        """
        res = 0

        while n!=0:
            res += 1
            n = n & (n-1)

        return res