Number of i Bits:Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the ).For example, the 32-bit integer “11” has binary representation 00000000000000000000000000001011, so the function should return 3.

题意：求出一个整数2进制表示时1的个数。

思路：位操作，一位一位右移，然后判断最后一位是否为1。

代码：

public class Solution {    // you need to treat n as an unsigned value    public int hammingWeight(int n) {        int count = 0;        while(n!=0){           count+=n&1;            n>>>=1;        }        return count;    }}