Given an integer `n`, return an array `ans` of length `n + 1` such that for each `i` (`0 <= i <= n`), `ans[i]` is the **number of 1 bits** in the binary representation of `i`.
Example 1
Input:n = 2
Output:[0,1,1]
Explanation:0 -> 0b0 has 0 one-bits, 1 -> 0b1 has 1, 2 -> 0b10 has 1.