Sort Colors

Problem Statement - link #

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.

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]

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

Solutions #

class Solution {
public:
    void sortColors(vector<int>& nums) {
        int z=0, o=0, t=nums.size()-1;
        while(o<=t){
            if(nums[t]==2) t--;
            else if(nums[t]==1) {
                swap(nums[t],nums[o]);
                o++;
            }else{
                swap(nums[t],nums[z]);
                if(o==z) o++;
                z++;
            }
        }
    }
};