链表
一个节点分为两部分,数据区和链接区, 链接区指向下一个节点
单项链表
a, b = b, a的本质
python中变量是一块单独的空间, 其中保存的是所代表对象的地址
单项链表的实现
"""单项链表的实现"""
class Node(object):
def __init__(self, elem):
self.elem = elem
self.next = None
def __repr__(self):
return "<Node: {}>".format(self.elem)
class SingleLinkList(object):
def __init__(self, node=None):
self.__head = node
def add(self, item):
node = Node(item)
if self.__head:
self.__head, node.next = node, self.__head
else:
self.__head = node
def append(self, item):
node = Node(item)
if self.__head:
cur = self.__head
while cur.next is not None:
cur = cur.next
cur.next = node
else:
self.__head = node
def travel(self):
if self.__head:
cur = self.__head
while cur is not None:
print(cur.elem)
cur = cur.next
def remove(self, item):
if self.__head:
cur = self.__head
while cur.next is not None:
if cur.next.elem == item:
cur.next = cur.next.next
break
cur = cur.next
else:
print("Not Exist")
else:
print("Not Exist")
def insert(self, pos, item):
i = 0
cur = self.__head
if pos == 0:
self.add(item)
elif pos + 1 > self.length:
raise ValueError
else:
while cur.next is not None:
i += 1
if i == pos:
new_node = Node(item)
cur.next, new_node.next = new_node, cur.next
break
elif i > pos:
raise ValueError
cur = cur.next
def search(self, item):
if self.__head:
cur = self.__head
while cur is not None:
if cur.elem == item:
print(cur.elem)
break
cur = cur.next
@property
def length(self):
count = 0
if self.__head:
cur = self.__head
while cur is not None:
count += 1
cur = cur.next
return count
def is_empty(self):
return self.__head is None
循环链表
循环链表的实现
"""循环链表的实现"""
class Node(object):
def __init__(self, elem):
self.elem = elem
self.next = None
def __repr__(self):
return "<Node: {}>".format(self.elem)
class CircleLinkList(object):
def __init__(self, node=None):
if node is None:
self._head = None
else:
self._head = node.next = node
def add(self, item):
node = Node(item)
if self._head:
cur = self._head
while cur.next != self._head:
cur = cur.next
last = cur
node.next, self._head = self._head, node
last.next = self._head
else:
self._head = node.next = node
def append(self, item):
node = Node(item)
if self._head:
cur = self._head
while cur.next != self._head:
cur = cur.next
last = cur
last.next, node.next = node, self._head
else:
self._head = node.next = node
def travel(self):
if self._head:
cur = self._head
while cur.next != self._head:
print(cur.elem, end=" ")
cur = cur.next
print(cur.elem)
def remove(self, item): # 单节点remove
if self._head:
cur = self._head
while cur.next != self._head:
cur = cur.next
last = cur
cur = self._head
if cur.elem == item:
self._head = last.next = cur.next
else:
while cur.next != self._head:
if cur.next.elem == item:
cur.next = cur.next.next
break
cur = cur.next
else:
print("Not Exist")
else:
print("Not Exist")
def insert(self, pos, item):
length = self.length
if pos == 0:
self.add(item)
elif pos == length:
self.append(item)
elif pos > length:
raise ValueError
else:
i = 0
cur = self._head
while cur.next != self._head :
i += 1
if i == pos:
node = Node(item)
cur.next, node.next = node, cur.next
break
cur = cur.next
def search(self, item):
if self._head:
cur = self._head
while cur.next != self._head:
if cur.elem == item:
print(cur.elem)
break
cur = cur.next
else:
if cur.elem == item:
print(cur.elem)
@property
def length(self):
count = 0
if self._head:
cur = self._head
while cur.next != self._head:
count += 1
cur = cur.next
count += 1
return count
def is_empty(self):
return self._head is None
if __name__ == '__main__':
s = CircleLinkList()
s.append(0)
s.append(1)
s.append(2)
s.append(3)
s.remove(0)
s.insert(3, 4)
s.search(1)
s.travel()
双向链表
双向链表的实现
"""双项链表的实现"""
class Node(object):
def __init__(self, elem):
self.pre = None
self.elem = elem
self.next = None
def __repr__(self):
return "<Node: {}>".format(self.elem)
class DoubleLinkList(object):
def __init__(self, node=None):
self.__head = node
def add(self, item):
node = Node(item)
if self.__head:
self.__head, self.__head.pre, node.next = node, node, self.__head
else:
self.__head = node
def append(self, item):
node = Node(item)
if self.__head:
cur = self.__head
while cur.next is not None:
cur = cur.next
cur.next, node.pre = node, cur
else:
self.__head = node
def travel(self):
if self.__head:
cur = self.__head
while cur is not None:
print(cur.elem, end=" ")
cur = cur.next
def remove(self, item):
if self.__head:
cur = self.__head
while cur.next is not None:
if cur.next.elem == item:
cur.next, cur.next.next.pre = cur.next.next, cur
break
cur = cur.next
else:
print("Not Exist")
else:
print("Not Exist")
def insert(self, pos, item):
i = 0
cur = self.__head
if pos == 0:
self.add(item)
elif pos + 1 > self.length:
raise ValueError
else:
while cur.next is not None:
i += 1
if i == pos:
new_node = Node(item)
cur.next, new_node.next, new_node.pre = new_node, cur.next, cur
break
elif i > pos:
raise ValueError
cur = cur.next
def search(self, item):
if self.__head:
cur = self.__head
while cur is not None:
if cur.elem == item:
print(cur.elem)
break
cur = cur.next
@property
def length(self):
count = 0
if self.__head:
cur = self.__head
while cur is not None:
count += 1
cur = cur.next
return count
def is_empty(self):
return self.__head is None
顺序表和链表统称线性表