单链表无head各种操作及操作实验

#encoding=utf-8

class ListNode:

def __init__(self,x):

self.val=x;

self.next=None;

 

#链表逆序

def reverse(head): #循环的方法反转链表

if head is None or head.next is None:

return head;

pre=None;

cur=head;

head2=0

while cur:

head2=cur;

tmp=cur.next;

cur.next=pre;

pre=cur;

cur=tmp;

return head2

#链表长度

def length(head):

pre = head

length = 0

while pre:

length += 1

pre = pre.next

return length

 

#追加节点

def add(head,data):

node=ListNode(data)

pre=head

 

while pre.next:

pre=pre.next

pre.next=node

 

#清空链表

def clear(head):

head.val=None

head.next=None

 

#获取节点

def get(head,index):

pre=head

index-=1

while index:

pre=pre.next

index-=1

return pre

 

#设置节点

def set(head,index,data):

n=get(head,index)

n.val=data

return n

 

#插入节点

def insert(head,index,data):

node=ListNode(data)

n=get(head,index-1)

node.next=n.next

n.next=node

 

#遍历链表

def show(head):

p=head

while p:

print p.val;

p=p.next;

 

 

 

 

#删除节点

def delete(head,index):

n=get(head,index-1)

n.next=n.next.next

 

 

head=ListNode(1); #测试代码

p1=ListNode(2); #建立链表1->2->3->4->None;

p2=ListNode(3);

p3=ListNode(4);

head.next=p1;

p1.next=p2;

p2.next=p3;

 

p=reverse(head); #输出链表 4->3->2->1->None

print '逆序:'

show(p)

clear(head)

print head.val,head.next

head=ListNode(1); #测试代码

p1=ListNode(2); #建立链表1->2->3->4->None;

p2=ListNode(3);

p3=ListNode(4);

head.next=p1;

p1.next=p2;

p2.next=p3;

print 'len:',length(head)#len: 4

add(head,5)

print 'len:',length(head)#len: 5

print get(head,3).val#3

print set(head,3,13).val#13

insert(head,3,12)

print'插入后：'

show(head)

print'删除后：'

delete(head,3)

show(head)