Quick sort with middle element selected as the pivot

问题

I have this code but the employer has asked me to pivot in the middle If anyone can help, please edit this code

def quicksort(sequence, low, high):
    if low < high:
        pivot = partition(sequence, low, high)
        quicksort(sequence, low, pivot - 1)
        quicksort(sequence, pivot + 1, high)

def partition(sequence, low, high):
    pivot = sequence[low]
    i = low + 1
    for j in range(low + 1, high + 1):
        if sequence[j] < pivot:
            sequence[j], sequence[i] = sequence[i], sequence[j]
            i += 1
    sequence[i-1], sequence[low] = sequence[low], sequence[i-1]
    return i - 1

回答1:

patel's answer switches from the question's Lomuto scheme to Hoare scheme. The simplest fix to the question's code would be swapping middle element with low element as the first line in partition

def partition(sequence, low, high):
    sequence[low],sequence[(low+high)//2] = sequence[(low+high)//2],sequence[low] #change
    pivot = sequence[low]
      ...

回答2:

change the partition method in the following way

def partition(sequence, low, high):
    sequence[low],sequence[(low+high)//2] = sequence[(low+high)//2],sequence[low]
    pivot = sequence[low]

D:

来源：https://stackoverflow.com/questions/57030369/quick-sort-with-middle-element-selected-as-the-pivot