Problem statement

https://binarysearch.com/problems/Just-Average/

Solution

Just check that s - k * (n - 1) in our numbers.

Complexity

It is O(n) for time and space.

Code

class Solution:
    def solve(self, nums, k):
        n, s = len(nums), sum(nums)
        return s - k * (n - 1) in nums