#双向链表----增删改查

'''
ADT   -------Abstract Data Type
单链表
双端链表
双向链表
'''
'''
#双向链表----增删改查
class NullLinkedError(BaseException):
    def __init_(self):
        super().__init__("null linked error")
class node():
    #content:创建节点，表示链表中元素，有三个属性
    #    pre-前驱结点地址
    #    data-数据
    #    next-后继节点地址
    def __init__(self, data, pre=None, next=None):
        self.__pre = pre
        self.__data = data
        self.__next = next
    def get_data(self):
        return self.__data
    def set_data(self,data):
        self.__data = data
    def get_pre(self):
        return self.__pre
    def set_pre(self,pre):
        self.__pre = pre
    def get_next(self):
        return self.__next
    def set_next(self,next):
        self.__next = next
class double_linked():
    def __init__(self, len= 0, first= None, last= None):
        self.__len = 0
        self.__first = first
        self.__last = last
    def get_len(self):
        return self.__len
    def set_len(self,len):
        self.__len = 0
    def get_first(self):
        return self.__first
    def set_first(self,first):
        self.__first = first
    def get_last(self):
        return self.__last
    def set_last(self,last):
        self.__last = last
    #插入
    def insert_first(self,data):
        n = node(data = data)
        #判断是否是空链表
        if self.__len == 0:
            self.__first = n
            self.__last = n
        else:
            n.set_next(self.__first)
            self.__first.set_pre(n)
            self.__first = n
        self.__len += 1
    def insert_last(self,data):
        n = node(data = data)
        #判断是否是空链表
        if self.__len == 0:
            self.__first = n
            self.__last = n
        else:
            n.set_pre(self.__last)
            self.__last.set_next(n)
            self.__last = n
        self.__len += 1
    def insert(self,data0,data):
        n = node(data = data)
        if self.__len == 0:
            raise NullLinkedError()
        else:
            currentNode = self.__first
            flag = False
            while currentNode != None:
                if currentNode.get_data() == data0:
                    if currentNode.get_next != None:
                        n.set_next(currentNode.get_next())
                        n.set_pre(currentNode)
                        currentNode.set_next(n)
                        currentNode.get_next().set_pre(n)
                        self.__len += 1
                    else:
                        self.insert_last(data)
                    flag = True
                    break
                else:
                    currentNode = currentNode.get_next()
            if flag:
                print("该数据插入成功")
            else:
                print("该数据插入失败")
    #删除头结点，若空则抛出异常，否则删除头元素
    def delete_first(self):
        if self.__len == 0:
            raise NullLinkedError()
        else:
            if self.__len == 1:
                self.__first = None
                self.__last = None
            else:
                self.__first = self.__first.get_next()
                self.__first.set_pre(None)
            self.__len -= 1
    #删除尾结点，若空则抛出异常，否则删除尾元素
    def delete_last(self):
        if self.__len == 0:
            raise NullLinkedError()
        else:
            if self.__len == 1:
                self.__first = None
                self.__last = None
            else:
                self.__last = self.__last.get_pre()
                self.__last.set_next(None)
            self.__len -= 1
    def delete(self,data):
        if self.__len == 0:
            raise NullLinkedError()
        elif self.__len == 1:
            if self.__first.get_data() == data:
                self.__first = None
                self.__last = None
                self.__len -= 1
        else:
            currentNode = self.__first
            while currentNode != None:
                if currentNode.get_data() == data:
                    if currentNode.get_pre() == None:
                        self.delete_first()
                    elif currentNode.get_next() == None:
                        self.delete_last()
                    else:
                        currentNode.get_pre().set_next(currentNode.get_next())
                        currentNode.get_next().set_pre(currentNode.get_pre())
                        self.__len -= 1
                    break
                else:
                    currentNode = currentNode.get_next()
    #更改头元素--若空则抛出异常，否则更改第一个结点数据
    def update_first(self,data):
        if self.__len == 0:
            raise NullLinkedError()
        else:
            self.__first.set_data(data)
    #更改尾元素，若空则抛出异常，否则更改最后一个节点数据
    def update_last(self,data):
        if self.__len == 0:
            raise NullLinkedError()
        else:
            self.__last.set_data(data)
    def update(self,data0,data):
        if self.__len == 0:
            raise NullLinkedError
        else:
            currentNode = self.__first
            flag = False
            while currentNode != None:
                if currentNode.get_data() == data0:
                    currentNode.set_data(data)
                    flag = True
                    break
                else:
                    currentNode = currentNode.get_next()
            if flag:
                print("修改成功啦啦啦")
            else:
                print("修改失败啦啦啦")
    #查看
    def show_info(self):
        if self.__len == 0:
            print("这是一个空链表")
        else:
            currentNode = self.__first
            while currentNode != None:
                print(currentNode.get_data())
                currentNode = currentNode.get_next()
    def length(self):
        return self.__len

d = double_linked()
d.insert_first("林徽因")
d.insert_first("蜘蛛侠")
d.insert_last("猴子")
d.insert_last("gly")
#d.delete_first()
#d.delete_last()
#d.update_first("666")
#d.update_last("猪猪侠")
#print(d.length())
d = double_linked()
d.insert_first("林徽因")
d.insert("林徽因","gly")
d.show_info()
d.delete("林徽因")
d.update("gly","咦")
d.show_info()
print(d.length())
'''