[Java/Python 3] Use array to record remaining slots.
java\n    private int[] count;\n    public ParkingSystem(int big, int medium, int small) {\n        count = new int[]{0, big, medium, small};\n    }\n    \n    
```java\n    private int[] count;\n    public ParkingSystem(int big, int medium, int small) {\n        count = new int[]{0, big, medium, small};\n    }\n    \n    public boolean addCar(int carType) {\n        return count[carType]-- > 0;\n    }\n```\n```python\n    def __init__(self, big: int, medium: int, small: int):\n        self.count = [0, big, medium, small]\n    def addCar(self, carType: int) -> bool:\n        self.count[carType] -= 1\n        return self.count[carType] >= 0\n```
['Java', 'Python3']