# coding:utf-8
class Node(object):
def __init__(self, elem):
self.elem = elem
self.next = None
class SingleLinkList(object):
def __init__(self, node=None):
self.__head = node
"""单链表"""
def is_empty(self):
"""判断链表是否为空"""
return self.__head == None
def length(self):
cur = self.__head
count = 0
while cur != None:
count += 1
cur = cur.next
return count
def travel(self):
"""遍历整个链表"""
cur = self.__head
while cur != None:
print("%s" % (cur.elem), end=" ")
cur = cur.next
print("")
def add(self, item):
"""链表头部添加元素"""
node = Node(item)
node.next = self.__head
self.__head = node
def append(self, item):
"""链表尾部添加元素"""
node = Node(item)
if self.is_empty():
self.__head = node
else:
cur = self.__head
while cur.next != None:
cur = cur.next
cur.next = node
def insert(self, pos, item):
"""指定位置添加元素"""
if pos <= 0:
self.add(item)
elif pos > self.length() - 1:
self.append(item)
else:
pre = self.__head
count = 0
while count < pos - 1:
count += 1
pre = pre.next
node = Node(item)
node.next = pre.next
pre.next = node
def remove(self, item):
"""删除节点"""
cur = self.__head
pre = None
while cur!=None:
if cur.elem == item:
if cur == self.__head:
self.__head = cur.next
else:
pre.next = cur.next
print(item,"已经删除")
return True
else:
pre = cur
cur = cur.next
print("不存在此节点",item)
return False
def search(self, item):
"""查找节点是否存在"""
cur = self.__head
while cur != None:
if cur.elem == item:
return True
else:
cur = cur.next
return False
if __name__ == '__main__':
sll = SingleLinkList()
print(sll.is_empty())
print(sll.length())
sll.append(1)
print(sll.is_empty())
print(sll.length())
sll.add(8)
sll.append(2)
sll.append(3)
sll.travel()
sll.insert(-1,9)
sll.travel()
sll.insert(2,100)
sll.travel()
sll.insert(10,200)
sll.travel()
sll.remove(100)
sll.travel()
sll.remove(9)
sll.travel()
sll.remove(900)
sll.remove(200)
sll.travel()
sll.remove(8)
sll.travel()
sll.remove(1)
sll.remove(2)
sll.travel()
sll.remove(3)
sll.travel()
sll.remove(2000)
sll.travel()