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: [15, 100, 389, 471, 129, 112, 68, 70, 423, 81, 481, 334, 67, 80, 277, 93, 387, 391, 161, 434]
A: 
[481, 100, 389, 471, 129, 112, 68, 70, 423, 81, 15, 334, 67, 80, 277, 93, 387, 391, 161, 434]