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75. Sort Colors (Medium)

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]

 

Constraints:

• 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?

Related Topics

[Sort] [Array] [Two Pointers]

Similar Questions

1. Sort List (Medium)
2. Wiggle Sort (Medium)
3. Wiggle Sort II (Medium)

Hints

Hint 1

A rather straight forward solution is a two-pass algorithm using counting sort.

Hint 2

Iterate the array counting number of 0's, 1's, and 2's.

Hint 3

Overwrite array with the total number of 0's, then 1's and followed by 2's.