Question

Using the code below, we need to implement the median-of-three method for selecting a pivot. If it is possible to add the code needed and any pseudo code as comments, that would be helpful.

Thank you

Code:

def quickSort(alist):
quickSortHelper(alist,0,len(alist)-1)

def quickSortHelper(alist,first,last):
if first<last:

splitpoint = partition(alist,first,last)

quickSortHelper(alist,first,splitpoint-1)
quickSortHelper(alist,splitpoint+1,last)

def partition(alist,first,last):
pivotvalue = alist[first]

leftmark = first+1
rightmark = last

done = False
while not done:

while leftmark <= rightmark and \
alist[leftmark] <= pivotvalue:
leftmark = leftmark + 1
print(alist)

while alist[rightmark] >= pivotvalue and \
rightmark >= leftmark:
rightmark = rightmark -1
print(alist)

if rightmark < leftmark:
done = True
else:
temp = alist[leftmark]
alist[leftmark] = alist[rightmark]
alist[rightmark] = temp
print(alist)

temp = alist[first]
alist[first] = alist[rightmark]
alist[rightmark] = temp

return rightmark

alist = [54,26,93,17,77,31,44,55,20]
quickSort(alist)
print(alist)