Given an array of strings nums containing n unique binary strings each of length n, return a binary string of length n that does not appear in nums. If there are multiple answers, you may return any of them.
Example 1:
Input: nums = ["01","10"] Output: "11"
Example 2:
Input: nums = ["00","01"] Output: "11"
Example 3:
Input: nums = ["111","011","001"] Output: "101"
Constraints:
n == nums.length1 <= n <= 16nums[i].length == n