10 二进制中1的个数

 1 public class Solution {
 2     public int NumberOf1(int n) {
 3         int count = 0;
 4         int flag = 1;
 5         while(flag!=0){
 6             if((flag & n)!=0)
 7                 count ++;
 8             flag = flag<<1;
 9         }
10         return count;
11     }
12 }

 1 public class Solution {
 2     public int NumberOf1(int n) {
 3         int count = 0;
 4         while(n!=0){
 5                count ++;
 6                n=((n-1)&n);
 7                }
 8         return count;
 9     }
10 }