Given an integer n, return all the strobogrammatic numbers that are of length n. You may return the answer in any order. A strobogrammatic number is a number that looks the same when rotated 180 degrees (looked at upside down). Example 1: Input: n = 2 Output: ["11","69","88","96"] Example 2: Input: n = 1 Output: ["0","1","8"] Constraints: 1 <= n <= 14