Given an integer array nums of length n, you want to create an array ans of length 2n where ans[i] == nums[i] and ans[i + n] == nums[i] for 0 <= i < n (0-indexed).
Specifically, ans is the concatenation of two nums arrays.
Return the array ans.
n == nums.length1 <= n <= 10001 <= nums[i] <= 1000nums = [1,2,1][1,2,1,1,2,1]nums = [1,3,2,1][1,3,2,1,1,3,2,1]