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.

注意兩點：1. 我用的 rightshift 是>>>, 是unsigned right shift

2. & 的優先級不如 ==， 所以要把&的兩個參數括起來

 1 public class Solution { 2     // you need to treat n as an unsigned value 3     public int hammingWeight(int n) { 4         int count = 0; 5         for (int i=0; i<32; i++) { 6             if ((n>>>i & 1) == 1) count++; 7         } 8         return count; 9     }10 }