func one_count(n int) int {
var count int
for ;n!=0; {
if n%2==1 {
count++
}
n /= 2
}
return count
}
func countBits(n int) []int {
var ans []int
for i:=0;i<=n;i++ {
ans = append(ans, one_count(i))
}
return ans
}