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.

[170, 498, 490, 349, 135, 345, 287, 182, 394, 23, 97, 14, 418, 274, 285, 78, 147, 215, 104, 387]
[170, 14, 490, 349, 135, 345, 287, 182, 394, 23, 97, 498, 418, 274, 285, 78, 147, 215, 104, 387]