Quicksort算法Python錯誤

Question

我正在嘗試使用Python實現Quicksort。 這是我的代碼：

import random

def quickSort(lst):
    randomIndex = random.randint(0,len(lst)-1)
    pivot = lst[randomIndex]
    greater = []
    less = []
    equal = []
    if len(lst) > 1:
        for num in lst:
            if num > pivot:
                greater.append(num)
            elif num == pivot:
                equal.append(num)
            else:
                less.append(num)
        return quickSort(less)+equal+quickSort(greater)
    else:
        return lst

def main():
    lst = [1000000,100000,1000,10000,100,10]
    sortedLst = quickSort(lst)
    print("Quicksorted List: ", sortedLst)

main()

當我運行我的代碼時，為什么會遇到以下錯誤：

ValueError: empty range for randrange() (0,0, 0)

Answer 1

唯一的問題是，即使當lst為空時，您也嘗試選擇randomIndex，只需將初始化移至if條件中即可確保它們不為空

import random

def quickSort(lst):
    if len(lst) > 1:
        randomIndex = random.randint(0,len(lst)-1)
        pivot = lst[randomIndex]
        greater = []
        less = []
        equal = []
        for num in lst:
            if num > pivot:
                greater.append(num)
            elif num == pivot:
                equal.append(num)
            else:
                less.append(num)
        return quickSort(less)+equal+quickSort(greater)
    else:
        return lst

def main():
    lst = [1000000,100000,1000,10000,100,10]
    sortedLst = quickSort(lst)
    print("Quicksorted List: ", sortedLst)

main()