Solutions to http://www.utsc.utoronto.ca/~bharrington/csca48/files/a48-tt1-2013.pdf

q1.py

from stack import Stack


def size(stk: Stack) -> int:
    """ Return the number of items on Stack stk, *without* modifying stk.
    (It’s OK if the contents of stk are modified during the execution of this
    function, as long as everything is restored before the function returns.)
    
    >>> st = Stack()
    >>> st.push(3); st.push(2); st.push(1)
    >>> size(st)
    3
    >>> st.pop()
    1
    """

    s = 0

    temp_stk = Stack()

    while not stk.is_empty():
        temp_stk.push(stk.pop())
        s += 1

    while not temp_stk.is_empty():
        stk.push(temp_stk.pop())

    return s

q2.py

def fib(n: int) -> int:
    """ Return the nth fibonacci number.
    Where the fibonacci numbers are defined as: 1, 1, 2, 3, 5, 8, 13
    (each number is the sum of he two previous numbers)
    
    >>> fib(4)
    3
    """

    return 1 if n <= 2 else fib(n - 1) + fib(n - 2)
  

q3.py

class BuildingCodeViolationError(Exception):
    pass


class InvalidBusinessError(Exception):
    pass


class BuildingCreationException(Exception):
    pass


class Room:
    def __init__(self, name: str, square_footage: float):
        self.name = name
        self.square_footage = square_footage


class Building:
    def __init__(self, address: str, rooms: list):
        self.address = address
        self.rooms = rooms

    def __repr__(self):
        s = 0

        for room in self.rooms:
            s += room.square_footage

        return s

    def rename_room(self, old: str, new: str):
        for room in self.rooms:
            if room.name == old:
                room.name = new
                return

        raise BuildingCreationException()


class House(Building):
    def __init__(self, addr: str, rms: list):
        if len(rms) > 10:
            raise BuildingCodeViolationError()

        Building.__init__(self, addr, rms)

    def __repr__(self):
        print("Welcome to our house")

        for room in self.rooms:
            print("{:s}, {:d}".format(room.name, room.square_footage))


class Business(Building):
    def __init__(self, addr: str, rms: list):
        for room in rms:
            if room.square_footage < 100 \
                    or room.name == "Bedroom":
                raise InvalidBusinessError()

        Building.__init__(self, addr, rms)

    def change_square_footage(self, n, new_footage):
        for room in self.rooms:
            if room.name == n:
                room.square_footage = new_footage
                return

        raise BuildingCreationException()


if __name__ == "__main__":
    try:
        build = input("Type of building?\n")
        address = input("Address of building?\n")
        num = int(input("Number of rooms?\n"))
        rooms = []

        while num > 0:
            name = input("Name of room?\n")
            square_footage = float(input("square_footage of room {:s}?\n"
                                         .format(name)))
            rooms.append(Room(name, square_footage))

        building = {"building": Building(address, rooms),
                    "house": House(address, rooms),
                    "business": Business(address, rooms)
                    }.get(build.lower())

    except BuildingCreationException:
        print("oops...")
    except (BuildingCodeViolationError, InvalidBusinessError):
        print("you can’t do that")