Leetcode 191 Number of 1 Bits

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.

Solution 1: easy bit manipulation 

 public class Solution {  
   // you need to treat n as an unsigned value  
   public int hammingWeight(int n) {  
     int count=0;  
     for (int i=0; i<32; i++) {  
       if ((n&1)==1) count++;  
       n>>=1;  
     }  
     return count;  
   }  
 }