记得原来学数据结构和算法基础，觉得很难，现在用python实现数据结构太Easy了。
以下是练习的树结构和双向链表结构。
#tree
class TreeNode:
def __init__(self,value):#value is used here,node is used other places
self.parent=None
self.value=value
self.children=[]
def add_child(self,n):
n.parent=self
self.children.append(n)
def digraph(self,g):#将树转换成networkx中的有向图。
if self.parent==None:
g.add_node(self.value,level=0)
for c in self.children:
g.add_node(c.value,level=1)
g.add_edge(self.value,c.value)
c.digraph(g)
def getroot(self):
if self.parent==None:
return self
return self.parent.getroot()
#double linkedlist
class LinkedListNode(object):
def __init__(self, value=None):
self.prev = None
self.next = None
self.value = value
def str_left(self):
s=str(self.value)
n=self.prev
while n!=None:
s+="->"+str(n.value)
n=n.prev
return s
def str_right(self):
s=str(self.value)
n=self.next
while n!=None:
s+="->"+str(n.value)
n=n.next
return s
def str(self):
return self.head().str_right()
def link_right(self,b):
self.next=b
b.prev=self
def link_left(self,b):
self.prev=b
b.next=self
def unlink_right(self):
b=self.next
self.next=None
if b!=None:
b.prev=None
def unlink_left(self):
b=self.prev
self.prev=None
if b!=None:
b.next=None
def head(self):
if self.prev==None:
return self
else:
return self.prev.head()
def tail(self):
if self.next==None:
return self
else:
return self.next.tail()
# def cut_prev(self):
# before=self.prev
# if before!=None:
# else:
# unlinkab(before,self)
def remove_self(self):
before=self.prev
after=self.next
self.unlink_left()
self.unlink_right()
if before!=None and after!=None:
before.link_right(after)