一、链表的定义
用链接关系显式表示元素之间顺序关系的线性表称为链接表或链表。
二、单链表的python实现
class Node(object):
"""定义节点"""
def __init__(self, elem):
self.elem = elem
self.next = None
class SingleLinkList(object):
"""单链表操作"""
def __init__(self, node=None):
"""初始化"""
self.__head = node
def is_empty(self):
"""链表是否为空"""
return self.__head == None
def length(self):
"""链表长度"""
# 定义游标，用来移动遍历节点
cur = self.__head
# 定义计数
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(cur.elem,end=" ")
cur = cur.next
print("")
def add(self, item):
"""链表头部添加元素，头插法"""
node = Node(item)
node.next = self.__head
self.__head = node
def append1(self, item):
"""链表尾部添加元素,尾插法"""
node = Node(item)
# if self.__head == None:
if self.is_empty():
self.__head = node
return
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
"""
if pos < 0 :
# 输入值小于0，默认为头插法
return self.add(item)
elif pos > self.length()-1:
# 输入值大于列表长度，默认为尾插法
self.append1(item)
else:
node = Node(item)
cur = self.__head
count = 0
while count < (pos-1):
count += 1
cur = cur.next
# 当循环退出时，cur指向pos-1的位置
node.next = cur.next
cur.next = node
def remove(self, item):
"""删除节点,只删除第一个找到的数据"""
cur = self.__head
pre = None
while cur != None:
if cur.elem == item:
# 先判断此节点是否是头节点
# if pre == None:
if cur == self.__head:
self.__head = cur.next
# 删除节点
else:
pre.next = cur.next
break
else:
pre = cur
cur = cur.next
return
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
三、单循环链表的python实现：
class Node(object):
"""定义节点"""
def __init__(self, elem):
self.elem = elem
self.next = None
class SingleCycleList(object):
"""单向循环链表操作"""
def __init__(self, node=None):
"""初始化"""
self.__head = node
if node:
node.next = node
def is_empty(self):
"""链表是否为空"""
return self.__head == None
def length(self):
"""链表长度"""
# 定义游标，用来移动遍历节点
if self.is_empty():
return 0
cur = self.__head
# 定义计数
count = 1
while cur.next != self.__head:
count += 1
cur = cur.next
return count
def travel(self):
"""遍历整个链表"""
if self.is_empty():
return 0
cur = self.__head
while cur.next != self.__head:
print(cur.elem, end=" ")
cur = cur.next
# 退出循环时，cur指向尾节点，但未打印尾节点元素
print(cur.elem)
def add(self, item):
"""链表头部添加元素，头插法"""
node = Node(item)
if self.is_empty():
self.__head = node
node.next = node
return
cur = self.__head
while cur.next != self.__head:
cur = cur.next
# 退出循环时，cur指向尾节点
node.next = self.__head
self.__head = node
cur.next = node
def append1(self, item):
"""链表尾部添加元素,尾插法"""
node = Node(item)
# if self.__head == None:
if self.is_empty():
self.__head = node
node.next = node
else:
cur = self.__head
while cur.next != self.__head:
cur = cur.next
cur.next = node
node.next = self.__head
def insert(self, pos, item):
"""指定位置添加元素
pos 从0开始
"""
if pos < 0 :
# 输入值小于0，默认为头插法
return self.add(item)
elif pos > self.length()-1:
# 输入值大于列表长度，默认为尾插法
self.append1(item)
else:
node = Node(item)
cur = self.__head
count = 0
while count < (pos-1):
count += 1
cur = cur.next
# 当循环退出时，cur指向pos-1的位置
node.next = cur.next
cur.next = node
def remove(self, item):
"""删除节点,只删除第一个找到的数据"""
if self.is_empty():
return
cur = self.__head
pre = None
while cur.next != self.__head:
if cur.elem == item:
# 先判断此节点是否是头节点
# if pre == None:
if cur == self.__head:
# 头结点的情况，找尾节点
rear = self.__head
while rear.next != self.__head:
rear = rear.next
self.__head = cur.next
rear.next = self.__head
# 删除节点
else:
# 中间节点
pre.next = cur.next
return
else:
pre = cur
cur = cur.next
# 退出循环时，cur指向尾节点
if cur.elem == item:
if cur == self.__head:
# 链表只有一个节点
self.__head = None
else:
pre.next = cur.next
def search(self, item):
"""查找节点是否存在"""
if self.is_empty():
return False
cur = self.__head
while cur.next != self.__head:
if cur.elem == item:
return True
else:
cur = cur.next
# 退出循环时，cur指向尾节点
if cur.elem == item:
return True
return False
四、双循环链表的python实现：
class Node(object):
"""定义节点"""
def __init__(self, item):
self.elem = item
self.next = None
self.prev = None
class DoubleLinkList(object):
"""双链表操作"""
def __init__(self, node=None):
"""初始化，构造"""
self.__head = node
def is_empty(self):
"""链表是否为空"""
return self.__head == None
def length(self):
"""链表长度"""
# 定义游标，用来移动遍历节点
cur = self.__head
# 定义计数
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(cur.elem, end=" ")
cur = cur.next
print("")
def add(self, item):
"""链表头部添加元素，头插法"""
node = Node(item)
node.next = self.__head
self.__head = node
node.next.prev = node
def append1(self, item):
"""链表尾部添加元素,尾插法"""
node = Node(item)
# if self.__head == None:
if self.is_empty():
self.__head = node
return
else:
cur = self.__head
while cur.next != None:
cur = cur.next
cur.next = node
node.prev = cur
def insert(self, pos, item):
"""指定位置添加元素
pos 从0开始
"""
if pos < 0:
# 输入值小于0，默认为头插法
return self.add(item)
elif pos > self.length() - 1:
# 输入值大于列表长度，默认为尾插法
self.append1(item)
else:
node = Node(item)
cur = self.__head
count = 0
while count < pos:
count += 1
cur = cur.next
# 当循环退出时，cur指向pos的位置
node.next = cur
node.prev = cur.prev
cur.prev.next = node
cur.prev = node
def remove(self, item):
"""删除节点,只删除第一个找到的数据"""
cur = self.__head
while cur != None:
if cur.elem == item:
# 先判断此节点是否是头节点
# if pre == None:
if cur == self.__head:
self.__head = cur.next
if cur.next:
# 判断链表是否只有一个节点
cur.next.prev = None
else:
cur.prev.next = cur.next
if cur.next:
# 判断是否为尾节点
cur.next.prev = cur.prev
break
else:
cur = cur.next
return
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