Definition: 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.
Input: [189, 419, 469, 313, 257, 264, 297, 233, 291, 244, 77, 493, 142, 479, 163, 87, 162, 42, 128, 94]

[189, 419, 469, 313, 257, 264, 297, 233, 291, 244, 77, 42, 142, 479, 163, 87, 162, 493, 128, 94]