'''
To implement linked list using references

x=[1,2,3] # x is the refenrece for [1,2,3]
print(x)
y=x # y is the reference of x
print(y)
y.append(89)
print(y)
print(x)
'''

Implementation of List ADT

class Node(object):
def init(self, x):
self.data=x
self.NextNode=None

class LinkedList(object):
def init(self):
self.Hnode=None

def Insert(self, x, i):
NewNode=Node(x)
if(i is 1):
NewNode.NextNode=self.Hnode #link1
self.Hnode=NewNode #link2

  else:
    pos=1
    tnode=self.Hnode
    while((tnode is not None) and(pos<i-1)):
        pos=pos+1
        tnode=tnode.NextNode
    temp=tnode.NextNode # temp is the ref of ith node
    tnode.NextNode=NewNode # the Next Node in (i-1)th node becomes reference of newly crated node      
    NewNode.NextNode=temp  #temp is  ith node before inserstion            

def Delete(self, n):
tnode=self.Hnode
if(n==1):
dnode=self.Hnode
self.Hnode=self.Hnode.NextNode
else:
i=1
while( (tnode is not None) and (i<n-1) ):
i=i+1
tnode=tnode.NextNode

  #tnode is refering to n-1th node  
  dnode=tnode.NextNode # dnode is refering to nth node
  tnode.NextNode=dnode.NextNode
del dnode  # OS will include space allotted for dnode into free memory  

def Search(self, x):
tnode=self.Hnode
while((tnode is not None) and (tnode.data is not x)):
tnode=tnode.NextNode
if(tnode is not None):
print("yes")
else:
print("No")
def PrintList(self):
print(self.Hnode)
tnode=self.Hnode
while(tnode is not None):
print(tnode.data)
tnode=tnode.NextNode

List1 = LinkedList() # List1 represents empty list
'''
n1=Node(89)
List1.Hnode=n1 #
#print(List1.Hnode.data)
n2=Node(11)
n1.NextNode=n2
n3=Node(17)
n2.NextNode=n3
'''

List1.Insert(21, 1)
List1.Insert(13,1)
List1.Insert(27,3)
List1.Insert(17, 2)
List1.PrintList()
List1.Delete(2)
List1.PrintList()
#List1.Search(270)