快速排序（NB）

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# _*_coding:utf-8_*_

def partition(li, left, right):
    tmp = li[left]
    while left < right:
        while left < right and li[right] >= tmp:  # 从右面找比tmp小的数
            right -= 1  # 往左走一步
        li[left] = li[right]  # 把右边的值写到左边空位上
        print(li, 'right')
        while left < right and li[left] <= tmp:
            left += 1
        li[right] = li[left]  # 把左边的值写到右边空位上
        print(li, 'left')
    li[left] = tmp  # 把tmp归位
    return left

def _quick_sort(li, left, right):
    if left < right:  # 至少两个元素
        mid = partition(li, left, right)
        _quick_sort(li, left, mid - 1)
        _quick_sort(li, mid + 1, right)

def quick_sort(li):
    _quick_sort(li, 0, len(li) - 1)

ls = [5, 7, 9, 4, 8, 3, 6, 1]

quick_sort(ls)

print(ls)