# 75. Sort Colors

#### Medium

***

Given an array `nums` with `n` objects colored red, white, or blue, sort them [**in-place**](https://en.wikipedia.org/wiki/In-place_algorithm) so that objects of the same color are adjacent, with the colors in the order red, white, and blue.

We will use the integers `0`, `1`, and `2` to represent the color red, white, and blue, respectively.

You must solve this problem without using the library's sort function.

 

**Example 1:**

```
Input: nums = [2,0,2,1,1,0]
Output: [0,0,1,1,2,2]
```

**Example 2:**

```
Input: nums = [2,0,1]
Output: [0,1,2]
```

 

**Constraints:**

* `n == nums.length`
* `1 <= n <= 300`
* `nums[i]` is either `0`, `1`, or `2`.

&#x20;

**Follow up:** Could you come up with a one-pass algorithm using only constant extra space?

```python
class Solution:
    def sortColors(self, nums: List[int]) -> None:
        """
        Do not return anything, modify nums in-place instead.
        """
        left = 0
        mid = 0
        right = len(nums) - 1
        while mid <= right:
            if nums[mid] == 0:
                nums[left], nums[mid] = nums[mid], nums[left]
                mid += 1
                left += 1
            elif nums[mid] == 1:
                mid += 1
            else:
                nums[right], nums[mid] = nums[mid], nums[right]
                right -= 1
        
```