Description

Given an array with n objects colored red, white or blue, sort them in-place so that objects of the same color are adjacent, with the colors in the order red, white and blue. Here, we will use the integers 0, 1, and 2 to represent the color red, white, and blue respectively.

Examples:

Input: [2,0,2,1,1,0]
Output: [0,0,1,1,2,2]

Solution:

class Solution(object):
    def sortColors(self, nums):
        """
        :type nums: List[int]
        :rtype: void 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[left], nums[i] = nums[i], nums[left]
                left += 1
                i += 1
            elif nums[i] == 1:
                i += 1
            else:
                nums[i], nums[right] = nums[right], nums[i]
                right -= 1