def partition(nums, left, right):

pivot = nums[left]

while left < right:

        while left < right and nums[right]>pivot:

                right -= 1

        nums[left] = nums[right]

        while left < right and nums[left] <= pivot:

                left += 1

        nums[right] = nums[left]

nums[left] = pivot

return left

def quicksort(nums, left, right):

if left > right:

return

pivot_idx = partition(nums, left, right)

quicksort(nums, left, pivot_idx+1)

quicksort(nums, pivot_idx-1, right)