vector<int> stones(int n, int a, int b) {
    vector<int> v;
    for(int i=0,j=n-1;i<n && j>=0;i++,j--){   
        int item=a*i+b*j;   //finding a,b multiples with i&j
        v.push_back(item);          
    }
    
    sort(v.begin(),v.end()); //Sorting  
    auto it = unique(v.begin(), v.end()); //to Remove Duplicates
    v.resize(distance(v.begin(), it));
    return v;
}