python 隨機快速排序法

import random 
def quicksort(arr,firstIndex, lastIndex):
    if firstIndex<lastIndex:
        divIndex=random_partition(arr,firstIndex, lastIndex)
        #print(divIndex)
        quicksort(arr,firstIndex,divIndex)
        quicksort(arr,divIndex+1, lastIndex)
    else:
        return

def partition(arr, firstIndex, lastIndex):
    i =firstIndex-1
    for j in range(firstIndex, lastIndex):
        if arr[j]<=arr[lastIndex]:
            i=i+1
            arr[i],arr[j]=arr[j],arr[i]
    arr[i+1],arr[lastIndex]=arr[lastIndex],arr[i+1]
    return i
def random_partition(arr,firstIndex, lastIndex):
    
    i=random.randint(firstIndex,lastIndex)
    arr[i],arr[lastIndex]=arr[lastIndex],arr[i]
    return partition(arr,firstIndex,lastIndex)
arr=[1,4,7,1,5,5,3,85,34,75,23,75,2,0]
print(arr[len(arr)-1])
print("initial array:\n",arr)
quicksort(arr,0,len(arr)-1)
print("result array:\n",arr)