Given a non negative integer number num. For every numbers i in the range 0 ≤ i ≤ num calculate the number of 1's in their binary representation and return them as an array.

Example:
For num = 5 you should return [0,1,1,2,1,2].

代码如下：

 1 public class Solution {
 2     public int[] countBits(int n) {
 3         int[] a=new int[n+1];
 4             
 5             for(int i=0;i<=n;i++)
 6             {
 7                 String s=Integer.toBinaryString(i);
 8             char[] ss=s.toCharArray();
 9             int count=0;
10             for(int j=0;j<ss.length;j++)
11             {
12                 if(ss[j]=='1')
13                     count++;
14             }
15             a[i]=count;
16             }
17             return a;
18     }
19 }