🏆Easiest solution in CPP / JAVA/ Python   | 2 Approaches | 100% efficient✅
\n//Cpp\n//Method 1:\n\n class Solution \n {\n   public:\n         vector<int> getConcatenation(vector<int>& nums)\n         {\n         int n = nums.size();\t 
```\n//Cpp\n//Method 1:\n\n class Solution \n {\n   public:\n         vector<int> getConcatenation(vector<int>& nums)\n         {\n         int n = nums.size();\t \n         vector<int> ans(2 * n);\n\t\t  for (int i = 0; i < n; i++)\n         {\n             ans[i] = nums[i];\n             ans[i + n] = nums[i];\n         }\n         return ans;\n     }\n\t \n };\n \n //Method 2:\nclass Solution \n{\npublic:\n        vector<int> getConcatenation(vector<int>& nums)\n        {\n            vector<int> ans;\n            for(int i=0;i<nums.size();i++)\n            {\n                ans.push_back(nums[i]);\n            }\n              for(int i=0;i<nums.size();i++)\n            {\n                ans.push_back(nums[i]);\n            }\n           return ans;\n        }\n};\n\n```\n```\n#Python \nfrom typing import List\n\nclass Solution:\n    def getConcatenation(self, nums: List[int]) -> List[int]:\n        return nums + nums\n```\n```\n\t\t\n//Java\n\nclass Solution {\n    public int[] getConcatenation(int[] nums) {\n        int[] concatenated = new int[nums.length * 2];\n        System.arraycopy(nums, 0, concatenated, 0, nums.length);\n        System.arraycopy(nums, 0, concatenated, nums.length, nums.length);\n        return concatenated;\n    }\n}\n\n\n```\n### STAY COOL STAY DISCIPLINED ...\n\n
['Array', 'C', 'Python', 'C++', 'Java', 'Python3']