Concatenation of Array

Easy

Given an array nums of length n, return an array ans of length 2n where ans[i] = nums[i] and ans[i+n] = nums[i].

Example 1

Input:  nums = [1,2,1]
Output: [1,2,1,1,2,1]

Example 2

Input:  nums = [1,3,2,1]
Output: [1,3,2,1,1,3,2,1]

Constraints

• 1 <= nums.length <= 1000
• 1 <= nums[i] <= 1000