Sort an array of 0s, 1s and 2s.cpp

class Solution
{
    public:
    void sort012(int a[], int n)
    {
      //Dutch National flag problem
        int low=0,high=n-1,mid=0;
        while(mid<=high)
        {
            if(a[mid]==0)
            {
                swap(a[low],a[mid]);
                low++; mid++;
            }
            else if(a[mid]==1)
            {
                mid++; 
            }
            else
            {
                swap(a[mid],a[high]);
                high--;
            }
        }
    }
    
};