将上面的代码优化，优化条件为： 1.优化站点类，包含头结点（头结点标志为#+线路号），尾结点（尾结点标志为*+end） 2.优化站点类储存方式为双向链表 3.优化公交线路类，可以对单条公交线路进行增删改查 4.优化公交线路类函数，创建一个菜单函数， 5.优化公交线路类，可以对单条公交线路中的站点进行增删改查

以下是对上述代码的优化：

class Node:
    def __init__(self, data=None, prev=None, next=None):
        self.data = data
        self.prev = prev
        self.next = next

class BusRoute:
    def __init__(self, route_no, start_station, end_station):
        self.route_no = route_no
        self.start_station = start_station
        self.end_station = end_station
        self.stations = Node('#+' + start_station)
        self.stations.next = Node('*+end', self.stations)

    def add_station(self, station_name, prev_station_name):
        current = self.stations
        while current.next.data != '*+end':
            if current.next.data.split('+')[1] == prev_station_name:
                new_station = Node(station_name, current, current.next)
                current.next.prev = new_station
                current.next = new_station
                return True
            current = current.next
        return False

    def remove_station(self, station_name):
        current = self.stations
        while current.next.data != '*+end':
            if current.next.data.split('+')[1] == station_name:
                current.next.next.prev = current
                current.next = current.next.next
                return True
            current = current.next
        return False

    def modify_station(self, old_station_name, new_station_name):
        current = self.stations
        while current.next.data != '*+end':
            if current.next.data.split('+')[1] == old_station_name:
                current.next.data = current.next.data.split('+')[0] + '+' + new_station_name
                return True
            current = current.next
        return False

    def search_station(self, station_name):
        current = self.stations
        while current.next.data != '*+end':
            if current.next.data.split('+')[1] == station_name:
                return True
            current = current.next
        return False

    def display_stations(self):
        current = self.stations
        while current.next.data != '*+end':
            print(current.next.data.split('+')[1])
            current = current.next

def menu():
    print("1. 创建公交线路")
    print("2. 添加站点")
    print("3. 删除站点")
    print("4. 修改站点")
    print("5. 查找站点")
    print("6. 显示站点")
    print("7. 退出")
    choice = int(input("请输入您的选择："))
    return choice

routes = []

while True:
    choice = menu()

    if choice == 1:
        route_no = input("请输入公交线路号：")
        start_station = input("请输入起点站名：")
        end_station = input("请输入终点站名：")
        route = BusRoute(route_no, start_station, end_station)
        routes.append(route)
        print("公交线路创建成功！")

    elif choice == 2:
        route_no = input("请输入要添加站点的公交线路号：")
        for route in routes:
            if route.route_no == route_no:
                station_name = input("请输入要添加的站点名：")
                prev_station_name = input("请输入该站点前面的站点名：")
                if route.add_station(station_name, prev_station_name):
                    print("站点添加成功！")
                else:
                    print("站点添加失败，请检查输入是否正确。")
                break
        else:
            print("未找到该公交线路，请检查输入是否正确。")

    elif choice == 3:
        route_no = input("请输入要删除站点的公交线路号：")
        for route in routes:
            if route.route_no == route_no:
                station_name = input("请输入要删除的站点名：")
                if route.remove_station(station_name):
                    print("站点删除成功！")
                else:
                    print("站点删除失败，请检查输入是否正确。")
                break
        else:
            print("未找到该公交线路，请检查输入是否正确。")

    elif choice == 4:
        route_no = input("请输入要修改站点的公交线路号：")
        for route in routes:
            if route.route_no == route_no:
                old_station_name = input("请输入要修改的站点名：")
                new_station_name = input("请输入新的站点名：")
                if route.modify_station(old_station_name, new_station_name):
                    print("站点修改成功！")
                else:
                    print("站点修改失败，请检查输入是否正确。")
                break
        else:
            print("未找到该公交线路，请检查输入是否正确。")

    elif choice == 5:
        route_no = input("请输入要查找站点的公交线路号：")
        for route in routes:
            if route.route_no == route_no:
                station_name = input("请输入要查找的站点名：")
                if route.search_station(station_name):
                    print("站点存在！")
                else:
                    print("站点不存在，请检查输入是否正确。")
                break
        else:
            print("未找到该公交线路，请检查输入是否正确。")

    elif choice == 6:
        route_no = input("请输入要显示站点的公交线路号：")
        for route in routes:
            if route.route_no == route_no:
                route.display_stations()
                break
        else:
            print("未找到该公交线路，请检查输入是否正确。")

    elif choice == 7:
        print("程序已退出。")
        break

    else:
        print("无效的选择，请重新输入。")