This problem appeared in ABC 271 today in just an easier version of this codeforce problem with $$$k = 0$$$ and $$$a_i \le 2^{30}$$$
Maybe it's a coincidence that the authors came up with the almost exact same problem.
Even if authors didn't copied the problem, its still an unfair since there is a direct advantage for people who have solved the problem on codeforces.
also it's found in geeksforgeeks : link