数据结构练习 单链表实现反转

#!/usr/bin/env python3

class LNode(object):
        def __init__(self, elem, next_=None):
                self.elem = elem
                self.next = next_

class ListError(ValueError):
        pass

class LList(object):
        def __init__(self):
                self.head = None
                self.num = 0

        def is_empty(self):
                return self.head is None

        def count(self):
                return self.num

        def prepend(self, elem):
                self.head = LNode(elem, self.head)
                self.num += 1

        def pop(self):
                if self.head is None:
                        raise ListError
                e = self.head.elem
                self.head = self.head.next
                self.num -= 1
                return e

        def append(self, elem):
                if self.head is None:
                        self.head = LNode(elem, self.head)
                        self.num += 1
                        return
                p = self.head
                while p.next:
                      p = p.next
                p.next = LNode(elem)
                self.num += 1

        def pop_last(self):
                if self.head is None:
                        raise ListError
                p = self.head
                if p.next is None:
                        e = p.elem
                        self.head = None
                        self.num -= 1
                        return e
                while p.next.next:
                        p = p.next
                e = p.next.elem
                p.next = None
                self.num -= 1
                return e
          
        def bianli(self):
                p = self.head
                li = []
                while p:
                        li.append(p.elem)
                        p = p.next
                return li

        def reverse(self):
                li = self.bianli()
                sl = LList()
                for i in li:
                        sl.prepend(i)
                return sl

if __name__ == '__main__':
        l = LList()
        l.append(1)
79　　      l.prepend(2)
        l.pop_last()
        l.append(3)
        l.append(4)
        l.append(5)
        li = l.bianli()
        print(li)
        sl = l.reverse()
        li = sl.bianli()
        print(li)
89                                                             

 结果：

[2,3,4,5]

[5,4,3,2]

好久没写数据结构了 回顾一下