Python实现链表操作
Task1 ---- 链表
题目
- 链表
- 实现单链表、循环链表、双向链表，支持增删操作
- 实现单链表反转
- 实现两个有序的链表合并为一个有序链表
- 实现求链表的中间结点
说明：
- 由于时间有限，循环链表暂时没有检测可行性
- 由于能力有限，部分资料有参考
- 和数组一样，由于个人比较懒，所以在一个文件写完，中间定义了各种需要调用的方法，代码可能会有点多，在后续会不断完善修改
参考链接
- https://blog.csdn.net/pythonkun/article/details/80722901
- https://blog.csdn.net/The__Apollo/article/details/78769400
源码
# coding=utf-8
class SingleNode:
def __init__(self, value, next_data=None):
self.data = value
self.next = next_data
class DoubleNode:
def __init__(self, value, prev=None, next=None):
self.prev = prev
self.data = value
self.next = next
class LinkList:
def __init__(self, data, double_link=False, loop=False):
self.header = None
if double_link:
self.double = True
if data:
if not loop:
self.header = DoubleNode(data[0])
link = self.header
for i in data[1:]:
node = DoubleNode(i, link)
link.next = node
link = link.next
else:
pass
# 由于时间有限，这里可能会出问题，还没来得及检测，建议直接pass
# self.header = DoubleNode(data[0])
# first = self.header
# link = self.header
# for i in data[1:]:
# node = DoubleNode(i, link)
# link.next = node
# link = link.next
# link.next = first
# first.prev = link
else:
raise IOError("Init error")
else:
self.double = False
if data:
if not loop:
self.header = SingleNode(data[0])
link = self.header
for i in data[1:]:
node = SingleNode(i)
link.next = node
link = link.next
else:
pass
# 单链表循环链表，有待测试
# self.header = SingleNode(data[0])
# first = self.header
# link = self.header
# for i in data[1:]:
# node = SingleNode(i)
# link.next = node
# link = link.next
# link.next = first
else:
raise IOError("Init error")
def length(self):
index = 0
link = self.header
while link.next:
index += 1
link = link.next
index += 1
return index
def is_empty(self):
if self.length() == 0:
return True
else:
return False
def insert(self, index, value):
if not self.double:
if self.is_empty():
if index < 0 or index > self.length():
raise IndexError("Link list is empty")
elif index == 0:
self.header = SingleNode(value)
else:
link = self.header
link_new = SingleNode(value)
index_num = 0
while link.next:
if index_num == index - 1:
link_new.next = link.next
link.next = link_new
break
else:
index_num += 1
link = link.next
else:
if self.is_empty():
if index < 0 or index > self.length():
raise IndexError("Link list is empty")
elif index == 0:
self.header = DoubleNode(value)
else:
link = self.header
link_new = DoubleNode(value)
index_num = 0
while link.next:
if index_num == index - 1:
link_new.next = link.next
link.next.prev = link_new
link_new.prev = link
link.next = link_new
break
else:
index_num += 1
link = link.next
def append(self, value):
if not self.double:
if isinstance(value, SingleNode):
node = value
else:
node = SingleNode(value)
if not self.header == None:
link = self.header
while link.next:
link = link.next
link.next = node
else:
self.header = node
else:
if isinstance(value, SingleNode):
node = value
else:
node = DoubleNode(value)
if not self.header == None:
link = self.header
while link.next:
link = link.next
link.next = node
node.prev = link
else:
self.header = node
def delete(self, index):
if not self.double:
link = self.header
index_num = 0
while link.next:
if index_num == index:
link.next = link.next.next
break
else:
index_num += 1
else:
link = self.header
index_num = 0
while link.next:
if index_num == index:
link.next = link.next.next
link.next.next.prev = link
break
else:
index_num += 1
# def update(self, index, value):
# if not isinstance(index, int):
# raise TypeError("Index must be integer")
# if isinstance(value, SingleNode):
# node = value
# else:
# node = SingleNode(value)
# if index < 0 or index > self.length():
# raise IndexError("Out of index")
# else:
# index_num = 0
# link = self.header
# while link.next:
# if index_num == index:
# link.
# else:
# index_num += 1
def get_index(self, value):
if self.is_empty():
raise IndexError("Link list is empty")
link = self.header
index = 0
while link:
if index < self.length():
if link.data == value:
return index
else:
link = link.next
index += 1
else:
raise IndexError("data is not exist")
def get_item(self, index):
if self.is_empty():
raise IndexError("Link list is empty")
if not isinstance(index, int):
raise IndexError("Index must be integer")
if index < 0 or index > self.length():
raise IndexError("Out of index")
link = self.header
index_num = 0
while link.next:
if index_num == index:
return link.data
else:
link = link.next
index_num += 1
def get_node(self, index):
if not isinstance(index, int):
raise IndexError("Index type error")
link = self.header
index_num = 0
while link.next:
if index_num == index:
mid_node = link
return mid_node
else:
link = link.next
index_num += 1
def reversed(self):
if not self.double:
link = self.__reversed_s(self.header)
self.header = link
else:
link = self.__reversed_d(self.header)
self.header = link
def __reversed_s(self, node):
"""
:param node:
:return:
"""
if node.next == None:
return node
link = self.__reversed_s(node.next)
node.next.next = node
node.next = None
return link
def __reversed_d(self, node):
"""
:param node:
:return:
"""
if node.next == None:
return node
link = self.__reversed_s(node.next)
node.next.next = node
node.prev = node.next
node.next = None
return link
def to_list(self):
if self.is_empty():
raise IOError("Link list is empty")
res_list = []
link = self.header
while link.next:
res_list.append(link.data)
link = link.next
res_list.append(link.data)
return res_list
def get_mid_node(self):
length = self.length()
if length % 2 == 0:
raise IOError("Link list have no middle node")
else:
mid_index = length // 2
middle_node = self.get_node(mid_index)
return middle_node
if __name__ == '__main__':
# # 单链表
# slink = LinkList([1, 2, 3, 4, 5])
# slink.insert(2, 8)
# slink.append(5)
# # slink.delete(2)
# # print(slink.length())
# # print(slink.is_empty())
# # print(slink.get_index(5))
# # print(slink.get_item(5))
# print(slink.to_list())
#
# # 获取中间节点
# mid_node = slink.get_mid_node()
# print(mid_node.data)
#
# # 链表反转
# slink.reversed()
# # print(slink.get_item(1))
# print(slink.to_list())
#
# # 两个有序链表合并
# sl1 = LinkList([1, 3, 5, 7, 9])
# sl2 = LinkList([2, 4, 6, 8, 10])
# res_list = sl1.to_list() + sl2.to_list()
# res_list.sort()
# res_link = LinkList(res_list)
# print(res_link.to_list())
# 双链表
slink = LinkList([1, 2, 3, 4, 5], double_link=True)
slink.insert(2, 8)
slink.append(5)
# slink.delete(2)
# print(slink.length())
# print(slink.is_empty())
# print(slink.get_index(5))
# print(slink.get_item(5))
print(slink.to_list())
# 获取中间节点
mid_node = slink.get_mid_node()
print(mid_node.data)
print(mid_node.prev.data)
# 链表反转
slink.reversed()
# print(slink.get_item(1))
print(slink.to_list())
# 两个有序链表合并
sl1 = LinkList([1, 3, 5, 7, 9])
sl2 = LinkList([2, 4, 6, 8, 10])
res_list = sl1.to_list() + sl2.to_list()
res_list.sort()
res_link = LinkList(res_list)
print(res_link.to_list())