Python Solution using HashMap
\nclass Solution:\n    def recoverArray(self, nums: List[int]) -> List[int]:\n        sz = len(nums)\n        nums.sort()\n        for i in range(1, sz):\n     
```\nclass Solution:\n    def recoverArray(self, nums: List[int]) -> List[int]:\n        sz = len(nums)\n        nums.sort()\n        for i in range(1, sz):\n            k, hashMap = nums[i] - nums[0], Counter(nums)\n            if k % 2 or k == 0:\n                continue\n            ans, gotIt = [], True\n            for j in range(sz):\n                if hashMap[nums[j]]:\n                    if nums[j] + k in hashMap and hashMap[nums[j] + k] > 0:\n                        ans.append(nums[j] + k // 2)\n                        hashMap[nums[j]] -= 1\n                        hashMap[nums[j] + k] -= 1\n                    else:\n                        gotIt = False\n                        break\n            if gotIt:\n                return ans\n        return []\n```
['Greedy', 'Python']