class LinkNode(object):
    def __init__(self, data, p = None):
        self.data = data
        self.next = p

class LinkList(object):
    def __init__(self):
        self.head = None

    #鏈表初始化函數，尾插法，插入data
    def initlist_tail(self, data):
        #創(chuàng)建頭結點埃难，其實是第一個有值節(jié)點
        self.head = LinkNode(data[0])
        p = self.head
        for i in data[1:]:
            #print(i)
            node = LinkNode(i)
            p.next = node
            p = p.next

    #判斷鏈表是否為空
    def isEmpty(self):
        p = self.head
        if p.next == None:
            print('The LinkList is Empty')
            return 1 #感覺是為了方便后續(xù)調用
        else:
            #print('The LinkList is not Empty')
            return 0

    #遍歷鏈表并輸出,用','隔開
    def ReadList(self):
        if self.isEmpty():
            exit(0)
        p = self.head
        while p:
            print(p.data, end = ',')
            p = p.next
        print('')

    #取鏈表長度
    def getLength(self):
        if self.isEmpty():
            exit(0)
        p = self.head
        lenth = 0
        while p:
            #print(p.data, end = ',')
            lenth += 1
            p = p.next
        print('lenth of the LinkList:', lenth)
        return lenth

    #在索引值為 index 的結點后插入結點key
    def insertElem(self, key, index):
        p = self.head
        j = 1
        while p and j < index:
            p = p.next
            j += 1
        if(p == 0 or j > index): #若出錯則退出
            exit(0)
            print('insert error')
        node = LinkNode(key)
        node.next = p.next
        p.next = node
        print('inserted LinkList:')
        self.ReadList()

    #刪除第 index個 結點后的那一個節(jié)點
    def deleteElem(self, index):
        p = self.head
        j = 1
        while p and j < index:
            p = p.next
            j += 1
        if(p == 0 or j > index): #若出錯則退出
            exit(0)
            print('insert error')
        q = p.next
        p.next = q.next
        print('deleted LinkList:')
        self.ReadList()

    #鏈表逆序
    def reverseList(self):
        pre, next, current = None, None, None
        current = self.head
        # 當前節(jié)點指向頭節(jié)點
        next = current.next
        # next 指向當前節(jié)點的下一個節(jié)點叠蝇，即將后面的節(jié)點存儲起來
        current.next = None
        # 令當前節(jié)點的next 指向None，即設為最后一個節(jié)點
        pre = current
        # 當前節(jié)點的前一個節(jié)點為當前節(jié)點
        current = next
        # 當前節(jié)點指向下一個節(jié)點開始下一輪循環(huán)
        while current.next != None:
            next = current.next
            # 存儲后面的鏈表
            current.next = pre
            # 將原本的前面的鏈表設為后面的
            pre = current
            current = next
            # 遍歷到鏈表最后一個節(jié)點時候铸鹰，將其指向前驅節(jié)點
        current.next = pre
        # 頭節(jié)點指向原來鏈表的最后一個節(jié)點
        self.head = current


data1 = [1, 2, 3, 4, 5]
data2 = [2, 0]
a = LinkList()
a.initlist_tail(data1)
a.reverseList()
a.ReadList() #輸出結果為1,2,3,4,5,
a.getLength() #輸出結果為lenth of the LinkList: 5
a.insertElem(6,3) #輸出結果為1,2,3,6,4,5,
a.deleteElem(3)#1,2,3,4,5,