text.cs

public class Booster : IBooster
{
	public int Multiplier {get; set;}

	public SelfieConfig [] Applies { get; set; }

	public void Apply(IPoly poly){
		foreach (var monomial in poly) {
			var selfie = monomial.Info as Selfie;			
			if (selfie != null && Applies.Contains(selfie.Config)) {
				monomial.Multiply(Multiplier);
			}
		}
	}
}

public class RatingConfig : ScriptableObject {
	public int Value { get; set; }
}

public class SelfieConfig : ScriptableObject {
	public RatingConfig[] Ratings { get; set; }

}

public class Rating {
	public RatingConfig Config { get; set; }

	public DateTime Start { get; set; }
}

public class Selfie {
	
	public HastTags HashTags { get; set; }
	public List<Rating> Ratings { get; } = new List<Rating>();
	public SelfieConfig Config { get; set; }
	
	public Poly Poly { 
		get {
			var poly = Poly.Constant(Rating.Value);
			poly.Info = this;
			if (HashTags != null) {
				poly.Multiply(HashTags.Value);
			}

			var ratingPoly = new Poly();
			foreach (var r in Ratings) {
				ratingPoly.Add(r.Value);
			}

			poly.Multiply(ratingPoly);

			return poly;
		}
	}
}


public class Player {

	public List<Selfie> selfies;
	public List<IBooster> boosters;
	public List<Friend> friends;

	public int FollowersAt(DateTime t0){
		var poly = new Poly();

		foreach (var s in selfies) {
			poly.Add(s.Poly);
		}

		foreach (var b in boosters) {
			b.Apply(poly);
		}

		return poly.ValueAt(t0);
	}
}