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.
1、思路：
2、复杂度：
3、代码：
public class Solution { // you need to treat n as an unsigned value public int hammingWeight(int n) { int cnt=0,i=1; while(i<=32) { if((n&1)==1) cnt++; n=n>>1; i++; } return cnt; } }
4、优化：
5、扩展：
原文：http://www.cnblogs.com/maydow/p/4643643.html