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Total Double Linked List in one.py
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Total Double Linked List in one.py
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# ***** DOUBLY LINKED LIST IN PYTHON *****
# Print from forward direction
# Print from backward derection
# Add end
# add begin
# Add after a node
# add before a node
# Delete at beginning
# Delete at the end
# Delete element at a given value
class Node:
def __init__(self,data):
self.data = data
self.nref = None
self.pref = None
class DoublyLL:
def __init__(self):
self.head = None
def print_ll(self):
if self.head is None:
print("The Doubly linked list is empty")
else:
n = self.head
while n is not None:
print(n.data)
n = n.nref
def print_ll_reverse(self):
if self.head is None:
print("The Doubly linked list is empty")
else:
n = self.head
while n.nref is not None:
n = n.nref
while n is not None:
print(n.data)
n = n.pref
def add_end(self,data):
new_node = Node(data)
if self.head is None:
self.head = new_node
else:
n = self.head
while n.nref is not None:
n = n.nref
n.nref = new_node
new_node.pref = n
def add_begin(self,data):
new_node = Node(data)
if self.head is None:
self.head = new_node
else:
new_node.nref = self.head
self.head.pref = new_node
self.head = new_node
def add_after_node(self,data,x):
new_node = Node(data)
n = self.head
while n is not None:
if n.data ==x:
break
n = n.nref
if n is None:
print("We can't add after None Value, out of bound")
else:
if n.nref is None:
n.nref = new_node
new_node.pref = n
else:
new_node.nref = n.nref
n.nref.pref = new_node
n.nref = new_node
new_node.pref = n
def add_before_node(self,data,x):
if self.head is None:
print("Linked List is Empty!")
return
if self.head.data == x:
new_node = Node(data)
self.head.pref = new_node
new_node.nref = self.head
self.head = new_node
return
n = self.head
while n.nref is not None:
if x == n.nref.data:
break
n = n.nref
if n.nref is None:
print("Given Node is not presnt in Linked List!")
else:
new_node = Node(data)
new_node.pref = n
new_node.nref = n.nref
n.nref.pref = new_node
n.nref = new_node
def delete_begine(self):
if self.head is None:
print("DLL is empty so can't delete")
return
if self.head.nref == None:
self.head = None
return
else:
self.head = self.head.nref
self.head.pref = None
def delete_end(self):
if self.head is None:
print("DLL is empty so can't delete")
return
else:
n = self.head
while n.nref is not None:
n = n.nref
n.pref.nref = None
def delete_by_value(self,x):
if self.head is None:
print("DLL is empty so can't delete")
return
if self.head.nref is None:
if self.head.data == x:
self.head = None
else:
print("Given value is not present")
return
if self.head.data == x:
self.head = self.head.nref
self.head.pref = None
return
else:
n = self.head
while n.nref is not None:
if n.data == x:
break
n = n.nref
if n.nref is not None:
n.pref.nref = n.nref
n.nref = None
n.pref = None
else:
if n.data ==x:
n.pref.nref = None
else:
print(f"Can't delete {x} as it is not present")
DLL = DoublyLL()
DLL.add_begin(20)
DLL.add_begin(10)
DLL.add_end(50)
DLL.add_after_node(30,20)
DLL.add_before_node(40,50)
DLL.delete_begine()
DLL.delete_end()
DLL.delete_by_value(100)
DLL.print_ll()
print("----------------------------")
DLL.print_ll_reverse()