import java.util.ArrayList;

public class SetLocomotivesGeneric <T>
{
    /// Список хранимых объектов
    private final ArrayList<T> _places;

    public int Count() {
        return _places.size();
    }

    // Ограничение на количество
    private final int _maxCount;

    public SetLocomotivesGeneric(int count) {
        _maxCount = count;
        _places = new ArrayList<>();
    }

    public int Insert (T locomotive) {
        return Insert(locomotive, 0);
    }

    public int Insert (T locomotive, int position) {
        if (position >= _maxCount|| position < 0) return -1;
        _places.add(position, locomotive);
        return position;
    }

    public T Remove (int position) {
        if (position >= _maxCount || position < 0) return null;
        T result = _places.get(position);
        _places.remove(position);
        return result;
    }

    public T Get(int position)
    {
        if (position >= _maxCount || position < 0)
        {
            return null;
        }
        return _places.get(position);
    }


    /// Проход по набору до первого пустого
    public Iterable<T> GetLocomotives()
    {
        /*for (var locomotive : _places)
        {
            if (locomotive != null)
            {
                yield return locomotive;
            }
            else
            {
                yield break;
            }
        }*/
        return _places;
    }
}