Python - Doubly Linked List Allows Append, Prepend, Insert at Index, Delete First, Delete Last, Delete at Index, Delete by Value, and View
Doubly Linked List in Python that allows append, prepend, insert at index, delete first element, delete last element, delete at index, delete by value, and view Linked List operations.
Try this code here: https://repl.it/@VinitKhandelwal/DoublyLinkedList
OUTPUT
View
[]
View
[10]
View
[10, 1]
View
[10, 1, 10]
View
[2, 10, 1, 10]
View
[2, 10, 1, 7, 10]
View
[3, 2, 10, 1, 7, 10]
View
[10, 3, 2, 10, 1, 7, 10]
View
[4, 10, 3, 2, 10, 1, 7, 10]
View
[10, 4, 10, 3, 2, 10, 1, 7, 10]
View
[4, 3, 2, 1, 7]
Try this code here: https://repl.it/@VinitKhandelwal/DoublyLinkedList
class DoublyLinkedList:
def __init__(self):
self.reset()
def reset(self):
self.length = 0
self.head = None
self.tail = None
def append(self, value):
new_node = Node(value)
if self.length == 0:
self.head = new_node
self.tail = self.head
else:
new_node.back_pointer = self.tail
self.tail.front_pointer = new_node
self.tail = new_node
self.length += 1
def prepend(self, value):
new_node = Node(value)
if self.length == 0:
self.head = new_node
self.tail = self.head
else:
new_node.front_pointer = self.head
self.head.back_pointer = new_node
self.head = new_node
self.length += 1
def insert_at(self, index, value):
new_node = Node(value)
if self.length == 0:
self.head = new_node
self.tail = self.head
elif index > self.length+1:
new_node.back_pointer = self.tail
self.tail.front_pointer = new_node
self.tail = new_node
print("Index not available. Appended at the end.")
else:
temp = self.head
if index == 0:
self.prepend(value)
self.length -= 1
elif index == self.length+1:
new_node.back_pointer = self.tail
self.tail.front_pointer = new_node
self.tail = new_node
else:
for i in range(0, index):
prev_temp = temp
temp = temp.front_pointer
prev_temp.front_pointer=new_node
new_node.back_pointer = prev_temp
new_node.front_pointer = temp
temp.back_pointer = new_node
self.length += 1
def popfirst(self):
if self.length < 2:
self.reset()
else:
self.head = self.head.front_pointer
self.head.back_pointer = None
self.length -= 1
def poplast(self):
if self.length < 2:
self.reset()
else:
self.tail = self.tail.back_pointer
self.tail.front_pointer = None
self.length -= 1
def delete_at(self, index):
if index == 0:
self.popfirst()
elif index == self.length-1:
self.poplast()
elif index < self.length:
temp = self.head
for i in range(0, index):
prev_temp = temp
temp = prev_temp.front_pointer
prev_temp.front_pointer = temp.front_pointer
temp.front_pointer.back_pointer = prev_temp
self.length -= 1
def delete(self, value):
front = self.head
back = self.tail
for i in range(0, int(self.length/2)):
if front.value == value:
if front == self.head:
self.popfirst()
else:
prev_front.front_pointer = front.front_pointer
prev_front.front_pointer.back_pointer = prev_front
self.length -= 1
prev_front = front
front = prev_front.front_pointer
if back.value == value:
if back == self.tail:
self.poplast()
else:
next_back.back_pointer = back.back_pointer
next_back.back_pointer.front_pointer = next_back
self.length -= 1
next_back = back
back = next_back.back_pointer
def view(self):
print("View")
temp = None
arr = []
for i in range(0, self.length):
if temp == None:
temp = self.head
else:
temp = temp.front_pointer
if temp is not None:
arr.append(temp.value)
print(arr)
class Node:
def __init__(self, value, back_pointer=None, front_pointer=None):
self.value = value
self.back_pointer = back_pointer
self.front_pointer = front_pointer
obj = DoublyLinkedList()
obj.view()
obj.prepend(10)
obj.view()
obj.append(1)
obj.view()
obj.append(10)
obj.view()
obj.prepend(2)
obj.view()
obj.insert_at(3, 7)
obj.view()
obj.prepend(3)
obj.view()
obj.prepend(10)
obj.view()
obj.prepend(4)
obj.view()
obj.prepend(10)
obj.view()
obj.delete(10)
obj.view()
View
[]
View
[10]
View
[10, 1]
View
[10, 1, 10]
View
[2, 10, 1, 10]
View
[2, 10, 1, 7, 10]
View
[3, 2, 10, 1, 7, 10]
View
[10, 3, 2, 10, 1, 7, 10]
View
[4, 10, 3, 2, 10, 1, 7, 10]
View
[10, 4, 10, 3, 2, 10, 1, 7, 10]
View
[4, 3, 2, 1, 7]
Comments
Post a Comment