Program 1
# Implementation of Doubly Linked List
class Node:
def __init__(self):
self.ladd=None
self.data=None
self.radd=None
class DoubleLinkedList:
def __init__(self):
self.start=None
self.count=0
# Create method of list
def createList(self):
n=int(input("Enter an element"))
self.start=Node()
self.start.ladd=None
self.start.data=n
self.start.radd=None
temp=self.start
self.count=self.count+1
choice=input("Want to continue")
while(choice=="Y" or choice=="y"):
n=int(input("Enter next element"))
newnode=Node()
newnode.ladd=None
newnode.data=n
newnode.radd=None
temp.radd=newnode
newnode.ladd=temp
temp=temp.radd
self.count=self.count+1
choice=input("Want to continue")
# Display method of list
def displayList(self):
if(self.start==None):
print("List not found")
else:
temp=self.start
while(temp!=None):
print(temp.data,end=" ")
temp=temp.radd
print("\nTotal Node is : ",self.count)
# Method for insert first
def insertFirst(self):
if(self.start==None):
print("List not found")
else:
n=int(input("Enter an element for insert"))
newnode=Node()
newnode.ladd=None
newnode.data=n
newnode.radd=None
newnode.radd=self.start
self.start.ladd=newnode
self.start=newnode
self.count=self.count+1
# Method for insert node at last position
def insertLast(self):
if(self.start==None):
print("List not found")
else:
n=int(input("Enter an element for insert at last"))
newnode=Node()
newnode.ladd=None
newnode.data=n
newnode.radd=None
last=self.start
while(last.radd!=None):
last=last.radd
last.radd=newnode
newnode.ladd=last
self.count=self.count+1
#Method for insert middle position
def insertMiddle(self):
if(self.start==None):
print("List not found")
else:
n=int(input("Enter an element for insert at middle"))
newnode=Node()
newnode.ladd=None
newnode.data=n
newnode.radd=None
pos=int(input("Enter middle position"))
if(pos>self.count):
print("Invalid position total node only: ",self.count)
else:
i=1
next=self.start
while(i<pos):
prev=next
next=next.radd
i=i+1
prev.radd=newnode
newnode.ladd=prev
newnode.radd=next
next.ladd=newnode
self.count=self.count+1
#Method for reverse display
def reverseDisplay(self):
if(self.start==None):
print("List not found")
else:
temp=self.start
while(temp.radd!=None):
temp=temp.radd
while(temp!=None):
print(temp.data,end=" ")
temp=temp.ladd
print("\nTotal Node is : ",self.count)
#Main Menu
mylist=DoubleLinkedList()
while(1):
print("\n-------------------------Doubly Linked List-----------------------")
print("1. Create")
print("2. Display")
print("3. Reverse Display")
print("4. Insert First")
print("5. Insert Middle")
print("6. Insert Last")
print("7. Delete First")
print("8. Delete Middle")
print("9. Delete Last")
print("10.Serching")
print("11. Exit")
print("-------------------------------------------------------------------")
choice=int(input("Enter your choice"))
if(choice==1):
mylist.createList()
elif(choice==2):
mylist.displayList()
elif(choice==3):
mylist.reverseDisplay()
elif(choice==4):
mylist.insertFirst()
elif(choice==5):
mylist.insertMiddle()
elif(choice==6):
mylist.insertLast()
else:
break
