# Problem Statement 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`. ## Constraints - `n == nums.length` - `1 <= n <= 1000` - `1 <= nums[i] <= 1000` # Solution This operation is a built-in feature in Python, and we can return the answer in one line. ```python return nums + nums ``` Time Complexity: O$(n)$ | Space Complexity: O$(n)$