Sort Colors
Updated Jan 31, 2026
Problem
Given an array nums 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.
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.
Constraints
n == nums.length
1 <= n <= 300
nums[i] is either 0, 1, or 2.
Follow Up
Can you solve it without using extra space and in one pass?
Examples
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]
Function Signature
def sortColors(self, nums: list[int]) -> None
How to Submit
Implement a Solution class with a sortColors method.
Your method will be called with the input parameters and should return the answer.