实现一个函数返回电影网络中最受好评的电影

Question

给定类:

public class Movie
{
    private readonly char movieId;
    private readonly float rating;
    private List<Movie> similarMovies; // Similarity is bidirectional
    public Movie(char movieId, float rating)
    {
        this.movieId = movieId;
        this.rating = rating;
        similarMovies = new List<Movie>();
    }
    public char getId()
    {
        return movieId;
    }
    public float getRating()
    {
        return rating;
    }
    public void addSimilarMovie(Movie movie)
    {
        similarMovies.Add(movie);
        movie.similarMovies.Add(this);
    }
    public List<Movie> getSimilarMovies()
    {
        return similarMovies;
    }     
    public static IList<Movie> getMovieRecommendations(Movie movie, int numTopRatedSimilarMovies)
    {
        //Implement this method         
        return null;
    }
}

从当前电影可达A(等级1.2)/B C (2.4) (3.6)/D(4.8) 之前在上面的例子中，边表示相似性，数字表示评级。getmovierrecommendations (A,2)应该返回C和D(排序顺序无关，因此它也可以返回D和C)getmovierrecommendations (A,4)应该返回A, B,C,D(它也可以以任何顺序返回这些，例如:B,C,D,A)getmovierrecommendations (A,1)应该返回D。注意从A到D的距离不重要

Answer 1

 public static HashSet<Movie> sd = new HashSet<Movie>();
    public static IList<Movie> getMovieRecommendations(Movie movie, int numTopRatedSimilarMovies)
    {
        sd.Add(movie);
        foreach (Movie m in movie.getSimilarMovies())
        {
            if (!sd.Contains(m))
                getMovieRecommendations(m, -1);
        }
        if(numTopRatedSimilarMovies > -1)
            return sd.OrderByDescending(o => o.rating).Take(numTopRatedSimilarMovies).ToList();            
        return null;
    }