A21083. 有n位同学的成绩已经从⼩到大排好序，现在对它执行下面这段以第一个元素为pivot 的快速排序，请问此次排序的时间复杂度是（ ）。def quicksort(a, l, r): if l >= r: return pivot = a[l] i, j = l, r while i < j: while i < j and a[j] >= pivot: j -= 1 while i < j and a…

有n位同学的成绩已经从⼩到大排好序，现在对它执行下面这段以第一个元素为pivot 的快速排序，请问此次排序的时间复杂度是（    ）。

def quicksort(a, l, r):
    if l >= r:
        return
    pivot = a[l]
    i, j = l, r
    while i < j:
        while i < j and a[j] >= pivot:
            j -= 1
        while i < j and a[i] <= pivot:
            i += 1
        if i < j:
            a[i], a[j] = a[j], a[i]
    a[l], a[i] = a[i], a[l]
    quicksort(a, l, i - 1)
    quicksort(a, i + 1, r)


if __name__ == "__main__":
    scores = [60, 70, 80, 90, 100]
    print("排序前: ", scores)
    quicksort(scores, 0, len(scores)-1)
    print("排序后: ", scores)  # 输出: [60, 70, 80, 90, 100]


def quicksort_with_log(a, l, r, depth=0):
    if l >= r:
        return
    print(f"递归深度{depth}，处理区间[{l},{r}]，数组: {a[l:r+1]}")
    pivot = a[l]
    i, j = l, r
    while i < j:
        while i < j and a[j] >= pivot:
            j -= 1
        while i < j and a[i] <= pivot:
            i += 1
        if i < j:
            a[i], a[j] = a[j], a[i]
    a[l], a[i] = a[i], a[l]
    quicksort_with_log(a, l, i-1, depth+1)
    quicksort_with_log(a, i+1, r, depth+1)


scores2 = [60,70,80,90,100]
print("\n递归过程: ")
quicksort_with_log(scores2, 0, 4)