Leetcode - Sort Colors Solution
1 min read

Leetcode - Sort Colors Solution

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.

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]

Example 3:

Input: nums = [0]
Output: [0]

Example 4:

Input: nums = [1]
Output: [1]


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

Follow up:

  • Could you solve this problem without using the library's sort function?
  • Could you come up with a one-pass algorithm using only O(1) constant space?

Solution in Python

from collections import Counter
class Solution:
    def sortColors(self, nums: List[int]) -> None:
        Do not return anything, modify nums in-place instead.
        count = Counter(nums)
        index = 0
        for i in [0,1,2]:
            while count[i]:
                nums[index] = i
                count[i] -= 1

Enjoying these posts? Subscribe for more

Adblocker detected! Please consider reading this notice.

We've detected that you are using AdBlock Plus or some other adblocking software which is preventing the page from fully loading.

That's okay. But without advertising-income, we can't keep making this site awesome.

We don't have any banner, Flash, animation, obnoxious sound, or popup ad. We do not implement these annoying types of ads!

We need money to operate the site, and almost all of it comes from our online advertising.

Please add thepoorcoder.com to your ad blocking whitelist or disable your adblocking software.