python 資料結構之單鏈表的實現

鍊錶的定義：

鍊錶(linked list)是由一組被稱為結點的資料元素組成的資料結構，每個結點都包含結點本身的資訊和指向下乙個結點的位址。由於每個結點都包含了可以鏈結起來的位址資訊，所以用乙個變數就能夠訪問整個結點序列。也就是說，結點包含兩部分資訊：一部分用於儲存資料元素的值，稱為資訊域；另一部分用於儲存下乙個資料元素位址的指標，稱為指標域。鍊錶中的第乙個結點的位址儲存在乙個單獨的結點中，稱為頭結點或首結點。鍊錶中的最後乙個結點沒有後繼元素，其指標域為空。

如下圖所示：

單鏈表的結構：

單鏈表的插入和刪除示意圖：

python實現**：

#
!/usr/bin/python
#-*- coding: utf-8 -*-
class
node(object):
def__init__(self,val,p=0):
self.data =val
self.next =p
class
linklist(object):
def__init__
(self):
self.head =0
def__getitem__
(self, key):
ifself.is_empty():
print
'linklist is empty.
'return
elif key <0  or key >self.getlength():
print
'the given key is error
'return
else
:            
return
self.getitem(key)
def__setitem__
(self, key, value):
ifself.is_empty():
print
'linklist is empty.
'return
elif key <0  or key >self.getlength():
print
'the given key is error
'return
else
:            self.delete(key)
return
self.insert(key)
definitlist(self,data):
self.head =node(data[0])
p =self.head
for i in data[1:]:
node =node(i)
p.next =node
p =p.next
defgetlength(self):
p =self.head
length =0
while p!=0:
length+=1p =p.next
return
length
defis_empty(self):
if self.getlength() ==0:
return
true
else
:            
return
false
defclear(self):
self.head =0
def        q =node(item)
if self.head ==0:
self.head =q
else
:            p =self.head
while p.next!=0:
p =p.next
p.next =q
defgetitem(self,index):
ifself.is_empty():
print
'linklist is empty.
'return
j =0
p =self.head
while p.next!=0 and j 
p =p.next
j+=1
if j ==index:
return
p.data
else
:            
print
'target is not exist!
'def
insert(self,index,item):
if self.is_empty() or index<0 or index >self.getlength():
print
'linklist is empty.
'return
if index ==0:
q =node(item,self.head)
self.head =q
p =self.head
post  =self.head
j =0
while p.next!=0 and j
post =p
p =p.next
j+=1
if index ==j:
q =node(item,p)
post.next =q
q.next =p
defdelete(self,index):
if self.is_empty() or index<0 or index >self.getlength():
print
'linklist is empty.
'return
if index ==0:
q =node(item,self.head)
self.head =q
p =self.head
post  =self.head
j =0
while p.next!=0 and j
post =p
p =p.next
j+=1
if index ==j:
post.next =p.next
defindex(self,value):
ifself.is_empty():
print
'linklist is empty.
'return
p =self.head
i =0
while p.next!=0 and
not p.data ==value:
p =p.next
i+=1
if p.data ==value:
return
i        
else
:            
return -1l =linklist()
l.initlist([1,2,3,4,5])
print l.getitem(4)
print l.getitem(5)
l.insert(4,40)
print l.getitem(3)
print l.getitem(4)
print l.getitem(5)
l.delete(5)
print l.getitem(5)
l.index(5)

python 資料結構之單鏈表的實現

Python資料結構之單鏈表實現

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