Color classification of sorting

A daily topic ing, Today is a day medium topic 75. Sort Colors

class Solution {
    
public:
    void sortColors(vector<int>& nums) {
    
        int len=nums.size();
        if(len<=1){
    
            return;
        }
        int i=0;
        int zero=0,two=len-1;
        while(i<=two){
    
            if(nums[i]==0){
    
                swap(nums[i],nums[zero]);
                zero++;
                i++;
            }
            else if(nums[i]==1){
    
                i++;
            }
            else{
    
                swap(nums[i],nums[two]);
                two--;
            }
        }
    }
};