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.

[161, 38, 129, 34, 32, 387, 172, 89, 220, 189, 257, 229, 218, 43, 268, 39, 210, 411, 22, 99]
[161, 38, 129, 34, 32, 387, 172, 89, 220, 189, 257, 229, 218, 43, 268, 39, 210, 22, 411, 99]