from typing import List

class Solution:

def sortColors(self, nums: List[int]) -> None:

red, white, blue = 0, 0, len(nums)

while white < blue:

if nums[white] < 1:

nums[red], nums[white] = nums[white], nums[red]

white += 1

red += 1

elif nums[white] > 1:

blue -= 1

nums[white], nums[blue] = nums[blue], nums[white]

else:

white += 1