Sort colors (dutch national flag problem)

"""
Bucket sort: TC is O(n).
There's this case nums[curr]==2, after swapping with right, we should not increase i since the number swapped back from p2 can be 0/1, which needs to be further processed

When curr pointer has passed left pointer, the number swapped from left can only be
1 as curr pointer has passeed left.

Both of them are tricky to understadn
"""

class Solution:
    def sortColors(self, nums: List[int]) -> None:
        """
        Do not return anything, modify nums in-place instead.
        """

        left = 0
        right = len(nums)-1
        i = 0

        while i <= right:
            if nums[i] == 0:
                nums[i], nums[left] = nums[left], nums[i]
                left += 1
            elif nums[i] == 2:
                nums[i], nums[right] = nums[right], nums[i]
                right -= 1
                i -= 1
            i += 1