C++ || vector stl || Used push_back Function of vector || Easiest
If you find this solution easy and well explantory then do upvote (press up symbol present on left side) \n\n        int length=nums.size();\n        for(int i=
**If you find this solution easy and well explantory then do upvote (press up symbol present on left side) **\n\n        int length=nums.size();\n        for(int i=0; i<length; i++){\n            nums.push_back(nums[i]);\n        }   \n        return nums;\n
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