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.

[76, 66, 180, 140, 291, 342, 333, 13, 343, 279, 206, 292, 290, 275, 398, 258, 139, 271, 236, 21]
[76, 66, 180, 140, 291, 342, 333, 398, 343, 279, 206, 292, 290, 275, 13, 258, 139, 271, 236, 21]