函数实现:
- 单链表的初始化;
- 单链表的判空;
- 单链表的长度;
- 单链表的插入节点:头插、尾插、随机插入;
- 单链表的遍历节点;
- 单链表的删除节点;
- 单链表的查找节点(搜索节点);
代码:
class Node(object):
"""节点"""
def __init__(self, elem):
self.elem = elem
self.next = None
class SingleLinkList(object):
"""单链表"""
def __init__(self, node = None):
self.__head = node
def is_empty(self):
"""链表是否为空"""
return self.__head == None
def length(self):
# 游标用来遍历节点
cur = self.__head
# 节点计数器,初始值影响while循环的判断条件
counter = 0
while cur != None :
counter += 1
cur = cur.next
return counter
def travel(self):
cur = self.__head
while cur != None:
print(cur.elem)
cur = cur.next
def add(self, item):
"""链表头部添加元素"""
# print("=====头插法=====")
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)
# print("=====尾插法=====")
# 特殊情况
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
@pos: 从0开始 例:insert(2,100)
"""
if pos <= 0 :
self.add(item)
elif pos > (self.length() - 1):
self.append(item)
else:
node = Node(item)
pre = self.__head
count = 0
while count < (pos - 1):
pre = pre.next
count += 1
# 当循环退出后,pre指向pos-1位置
node.next = pre.next
pre.next = node
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
# 难度系数高
def remove(self, item):
cur = self.__head
pre = None
while cur != None:
if cur.elem == item:
# 判断此节点是否为头节点
if cur == self.__head:
self.__head = cur.next
else:
pre.next = cur.next
break
# pass
else:
pre = cur
cur = cur.next