Given a map Map<String, List> userSongs with user names as keys and a list of all the songs that the user has listened to as values.

Also given a map Map<String, List> songGenres, with song genre as keys and a list of all the songs within that genre as values. The song can only belong to only one genre.

The task is to return a map Map<String, List>, where the key is a user name and the value is a list of the user's favorite genre(s). Favorite genre is the most listened to genre. A user can have more than one favorite genre if he/she has listened to the same number of songs per each of the genres.

Example 1:

Input:

userSongs = {

"David": ["song1", "song2", "song3", "song4", "song8"],

"Emma": ["song5", "song6", "song7"]

},

songGenres = {

"Rock": ["song1", "song3"],

"Dubstep": ["song7"],

"Techno": ["song2", "song4"],

"Pop": ["song5", "song6"],

"Jazz": ["song8", "song9"]

}

Output: {

"David": ["Rock", "Techno"],

"Emma": ["Pop"]

}

Explanation:

David has 2 Rock, 2 Techno and 1 Jazz song. So he has 2 favorite genres.

Emma has 2 Pop and 1 Dubstep song. Pop is Emma's favorite genre.

public class Main {

public static Map<String, List<String>> favoritegenre(Map<String, List<String>> userMap, Map<String, List<String>> genreMap) {

}

public static void main(String[] args) {
        HashMap<String, List<String>> userSongs = new HashMap<>();

        userSongs.put("David", Arrays.asList(new String[]{"song1", "song2", "song3", "song4", "song8"}));

        userSongs.put("Emma", Arrays.asList(new String[]{"song5", "song6", "song7"}));

        HashMap<String, List<String>> songGenres = new HashMap<>();

        songGenres.put("Rock", Arrays.asList(new String[]{"song1", "song3"}));

        songGenres.put("Dubstep", Arrays.asList(new String[]{"song7"}));

        songGenres.put("Techno", Arrays.asList(new String[]{"song2", "song4"}));

        songGenres.put("Pop", Arrays.asList(new String[]{"song5", "song6"}));

        songGenres.put("Jazz", Arrays.asList(new String[]{"song8", "song9"}));

        Map<String, List<String>> res = favoritegenre(userSongs, songGenres);

        System.out.println(res);
}

}