package counting_bits; import java.util.Arrays; import java.util.stream.Collectors; /** * @author vision * @since 2017/10/10 下午7:37 */ public class Solution { public static void main(String[] args) { System.out.println(Arrays.stream(new Solution().countBits(10)).boxed().map(Object::toString) .collect(Collectors.joining(","))); } public int[] countBits(int num) { int[] r = new int[num + 1]; for (int i = 1; i <= num; ++i) { r[i] = r[i >> 1] + (i & 1); } return r; } }