I know something about RAII principle which says allocate memory in constructor and deallocate in destructor; But problem is: i wanna use interfaces(classes with only abstract methods, at least one);
And i try to create class-variable of interface type and initialize this variable in cotructor, for example:

class problem_solver
{
private:

    path_finder *_path_finder;

    area_divider *_divider;

//other methods
};


problem_solver::problem_solver(path_finder *path_finder, area_divider *divider)
    : _path_finder(path_finder), _divider(divider)
{

}

interface path_finder:

class path_finder
{
public:

    virtual std::vector<std::pair<node *, double>> find_shortest_path(graph const &graph, node *start_node, node *finish_node) = 0;

    virtual ~path_finder() = default;
};

And the main problem is there. Because there's no variant to followe RAII-principle, because i need to allocate object and deallocate it manually;

How can i fix it?