You will be given a definition of a task first, then some input of the task.
In this task, you are given a list of unique integers you need to swap the positions of maximum and minimum element in the list and return the updated list.

[146, 354, 466, 465, 481, 390, 64, 176, 347, 420, 459, 386, 299, 468, 15, 161, 18, 422, 300, 188]
Output:
[146, 354, 466, 465, 15, 390, 64, 176, 347, 420, 459, 386, 299, 468, 481, 161, 18, 422, 300, 188]