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.
Q: [134, 286, 251, 323, 396, 64, 294, 191, 75, 189, 386, 455, 30, 116, 287, 96, 420, 475, 382, 186]
A: 
[134, 286, 251, 323, 396, 64, 294, 191, 75, 189, 386, 455, 475, 116, 287, 96, 420, 30, 382, 186]