'''作业三：多级菜单

三级菜单

可依次选择进入各子菜单

所需新知识点：列表、字典

'''

data = {

    "北京":{

        "昌平":{

            "沙河":{"oldboy","test"},

            "天通苑":{"链家地产","我爱我家"}

        },

        "朝阳":{

            "望京":{"奔驰","陌陌"},

            "国贸":{"CICC","HP"},

            "东直门":{"Advent","飞信"},

        },

        "海淀":{},

    },

    '山东':{

        "德州":{},

        "青岛":{},

        "济南":{},

    },

    "广东":{

        "东莞":{},

        "常熟":{},

        "佛山":{},

    },

}

exit_flag = False

while not exit_flag:

    for i in data:

        print(i)

    choice = input("选择进入1层>>>:")

    if choice in data:

        while not exit_flag:

            for i2 in data[choice]:

                print("\t",i2)

            choice2 = input("选择进入2层>>>:")

            if choice2 in data[choice]:

                while not exit_flag:

                    for i3 in data[choice][choice2]:

                        print("\t\t", i3)

                    choice3 = input("选择进入4层>>>:")

                    if choice3 in data[choice][choice2]:

                        for i4 in data[choice][choice2][choice3]:

                            print("\t\t",i4)

                        choice4 = input("最后一层，按b返回>>>:")

                        if choice4 == "b":

                            pass

                        elif choice4 == "q":

                            exit_flag = True

                    if choice3 == "b":

                        break

                    elif choice3 == "q":

                        exit_flag = True

            if choice2 == "b":

                break

            elif choice2 == "q":

                exit_flag = True