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 { public: int hammingWeight(uint32_t n) { int cnt = 0; while(n){ cnt++; n=n&(n-1); } return cnt; } };
原文：http://www.cnblogs.com/zengzy/p/5052293.html