follow up :
kth largest number (quick select)
find median sort arrays( based on kth, 2 pointers, divide and conquer )

快排模板

def main():
    length = int(input())
    nums = [int(x) for x in input().split()]
    quicksort(nums, 0, length - 1)
    for i in nums:
        print(i, end = ' ')


def quicksort(nums, start, end):
    if start >= end :
        return 
    left, right = start, end
    pivot = nums[(start + end) // 2]

    while left <= right:
        while left <= right and nums[left] < pivot:
            left += 1
        while left <= right and nums[right] > pivot:
            right -= 1
        if left <= right:
            nums[left], nums[right] = nums[right], nums[left]
            left += 1
            right -=1
    quicksort(nums, start, right)
    quicksort(nums, left, end)

main()