上次单链表中有个问题，就是remove 方法有误，在这里已经修正了，下面是双链表的实现。其实，双链表已比较简单，就是在存储节点中加上一个指向上个节点的引用（呵呵，这好像是java的术语） 具体代码如下:
# -*- coding: cp936 -*-
#---------------------------------------------
#
#author chile
#version 1.0
#since
#date
#desc 双链表
#
#
#
#---------------------------------------------
class DoubleLinkList:
def __init__(self):
self.root = DoubleLinkList.Entry()
self.entry = self.root
self.list = list()
self.tally = 0
#新增的数据都是插入在尾部
def add(self,value):
temp = self.Entry(pre = self.entry,value = value)
self.entry.next = temp
self.entry = temp
self.tally += 1
#在头部添加
def addFirst(self,value):
entry = self.root.next
temp = self.Entry(pre = self.root , next = entry,value = value)
self.root.next = temp
self.tally += 1
def get(self,index):
if index > self.tally or index < 0:
return #其实应该抛出异常
mid = self.tally / 2
e = self.root.next
if index < mid:
for i in range(index):
e = e.next
else:
for i in range(self.tally):
if (i == index):
break
e = e.next
return e.value
def getLast(self):
return self.entry.value
def getFirst(self):
return self.root.next.value
def remove(self,value):
e = self.root.next
self.removeEntry(self.root,e, value)
if self.isRemove:
self.tally -= 1
def removeEntry(self,pre,current,value):
self.isRemove = False
if current == None:
self.isRemove = False
return
if current.value == value:
pre.next = current.next
self.isRemove = True
else:
self.removeEntry(current,current.next, value)
def removeFirst(self):
root = self.root
entry = root.next;
root.next = entry.next
entry.next.pre = root
self.tally -= 1
def size(self):
return self.tally
def all(self):
self.list = list()
self.iterator(self.root.next)
return self.list
def iterator(self,entry):
if entry != None:
self.list.append(entry.value)
self.iterator(entry.next)
#内部类 用于存放节点的值，以及下个点的引用
class Entry:
def __init__(self, pre = None , next = None , value = None):
self.next = next #下一个节点
self.pre = pre #上一个节点
self.value = value #节点存储的值
link = DoubleLinkList()
link.add(1)
link.add(2)
link.addFirst(3)
link.add(5)
link.add(4)
link.add(7)
link.remove(5)
print link.all(), link.size()
link.addFirst(5)
print link.all(), link.size()
link.removeFirst()
print link.all(), link.size()
print link.getFirst() , link.getLast() , link.get(3)
水平有限哈，写的比较简单。如果有什么问题，请指正。希望和有兴趣的共同交流。