Problem
A different method for choosing the pivot in quicksort is to take the median of the first, last, and central keys of the list. Describe the modifications needed to the function quick_sortto implement this choice. How much extra computation will be done? For n = 7, find an ordering of the keys 1, 2, ... , 7 that will force the algorithm into its worst case. How much better is this worst case than that of the original algorithm?