SORT THE COLORS LEETCODE SOLUTION C++ OR SORT 0 1 2 IN AN ARRAY

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.

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.

SOLUTION C++:

`class Solution {
public:
void sortColors(vector& nums) {
int n=nums.size();
int low = 0, mid = 0, high = n - 1; // 3 pointers

while (mid <= high) {
    if (nums[mid] == 0) {
        swap(nums[low], nums[mid]);
        low++;
        mid++;
    }
    else if (nums[mid] == 1) {
        mid++;
    }
    else {
        swap(nums[mid], nums[high]);
        high--;
    }
}
}

};`