链表有什么用
数组: 优点: 通过索引(数组下标)可以很快地访问数组元素;缺点: 插入/删除元素需要对数组进行调整, 效率低;
链表:优点：插入/删除速度很快，而且不用对整个链表进行调整；缺点：只能进行顺序访问，不能随机访问（像数组一样用下标）；
所以，链表在一些需要快速插入／删除，而不太关心或者不需要随机访问的情况下使用
首先创建Node类
class Node:
def __init__(self,initdata):
self.data = initdata
self.next = None
def getData(self):
return self.data
def getNext(self):
return self.next
def setData(self,newdata):
self.data = newdata
def setNext(self,newnext):
self.next = newnext
创建操作链表的类
class UnorderedList:
def __init__(self):
self.head = None
def isEmpty(self):
self.head == None
def add(self,item):
temp = Node(item)
temp.setNext(self.head)
self.head = temp
def size(self):
current = self.head
count = 0
while current != None:
count = count + 1
current = current.getNext()
return count
def search(self,item):
current = self.head
found = False
while current != None and not found:
if current.getData() == item:
found = True
else:
current = current.getNext()
return found
def getvalue(self):
current = self.head
currarr = []
while current != None:
currarr.append(current.getData())
current = current.getNext()
return currarr
def remove(self,item):
current = self.head
previous = None
found = False
while not found:
if current.getData() == item:
found = True
else:
previous = current
current = current.getNext()
if previous == None:
self.head = current.getNext()
else:
previous.setNext(current.getNext())
