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...
Given an integer, write a function to determine if it is a power of two. 判断一个数是不是2的若干次幂？第一个想法，首个bit位为1，其余全为0.优美解法：只有2的若干次幂和自身减1的每一个bit位不同，所以n &（n-1） ！= 0 说明...
