2122. Recover the Original Array

Alice had a 0-indexed array arr consisting of n positive integers. She chose an arbitrary positive integer k and created two new 0-indexed integer arrays lower and higher in the following manner: - lower[i] = arr[i] - k, for every index i where 0 <= i < n - higher[i] = arr[i] + k, for every index i where 0 <= i < n Unfortunately, Alice lost all three arrays. However, she remembers the integers