1class Material:
  2    density = None
  3
  4    def __init__(self, mass):
  5        self.mass = mass
  6        self._used = False
  7
  8    @property
  9    def volume(self):
 10        return self.mass / self.density
 11
 12
 13class Concrete(Material):
 14    density = 2500
 15
 16
 17class Brick(Material):
 18    density = 2000
 19
 20
 21class Stone(Material):
 22    density = 1600
 23
 24
 25class Wood(Material):
 26    density = 600
 27
 28
 29class Steel(Material):
 30    density = 7700
 31
 32class Factory:
 33    all_valid_materials = []
 34    dynamic_classes = {}
 35
 36    def __init__(self):
 37        self.materials = {
 38            "Concrete": Concrete,
 39            "Brick": Brick,
 40            "Stone": Stone,
 41            "Wood": Wood,
 42            "Steel": Steel,
 43        }
 44        self.valid_materials = []
 45        self.invalid_materials = []
 46
 47    def _mark_as_used(self, material):
 48        if material._used:
 49            raise AssertionError("Материалът вече е използван в тази сплав.")
 50        material._used = True
 51
 52    def _create_dynamic_class(self, materials):
 53        base_classes = sorted([mat.__class__.__name__ for mat in materials])
 54        class_name = "_".join(base_classes)
 55
 56        if class_name not in Factory.dynamic_classes:
 57            avg_density = sum(mat.density for mat in materials) / len(materials)
 58            new_class = type(
 59                class_name,
 60                (Material,),
 61                {"density": avg_density}
 62            )
 63            Factory.dynamic_classes[class_name] = new_class
 64
 65        return Factory.dynamic_classes[class_name]
 66
 67    def handle_args(self, args):
 68        for material in args:
 69            self._mark_as_used(material)
 70        dynamic_class = self._create_dynamic_class(args)
 71        new_instance = dynamic_class(sum([material.mass for material in args]))
 72        self.invalid_materials.extend(args)
 73        return new_instance
 74
 75    def handle_kwargs(self, kwargs):
 76        instances = []
 77        for name, mass in kwargs.items():
 78            material_class = self.materials.get(name) or Factory.dynamic_classes.get(name)
 79            if material_class is None:
 80                raise ValueError("Невалидно име на материал")
 81            material_instance = material_class(mass)
 82            instances.append(material_instance)
 83            self.valid_materials.append(material_instance)
 84        return tuple(instances)
 85
 86    def __call__(self, *args, **kwargs):
 87        if args and kwargs:
 88            raise ValueError("Фабриката не може да се извика и с двата типа аргументи.")
 89        if not args and not kwargs:
 90            raise ValueError("Фабриката трябва да се извика или с позиционен, или с именуван параметър.")
 91        if args:
 92            if isinstance(args[0], Material):
 93                return self.handle_args(args)
 94            else:
 95                raise ValueError("Невалидни аргументи.")
 96        if kwargs:
 97            return self.handle_kwargs(kwargs)
 98
 99    def can_build(self, required_volume):
100        total_volume = sum(mat.volume for mat in self.valid_materials if not mat._used)
101        return total_volume >= required_volume
102
103    @classmethod
104    def can_build_together(cls, required_volume):
105        total_volume = sum(mat.volume for factory in Factory.all_valid_materials for mat in factory.valid_materials)
106        return total_volume >= required_volume