| 6 | |
| 7 | #class to create the Doubly Linked List |
| 8 | class DoublyLinkedList: |
| 9 | |
| 10 | #constructor to initialise the doubly linked list, head and tail initialised to 'None' |
| 11 | def __init__(self): |
| 12 | self.head = self.tail = None |
| 13 | |
| 14 | #method to check if the doubly linked list is empty or not |
| 15 | def isEmpty(self): |
| 16 | if self.head == self.tail == None: |
| 17 | return True |
| 18 | return False |
| 19 | |
| 20 | #method to add an element in front the list i.e. head |
| 21 | def addFront(self, x): |
| 22 | new_node = Node(x) |
| 23 | if (self.isEmpty()): |
| 24 | self.head = self.tail = new_node |
| 25 | new_node.prev = None |
| 26 | return |
| 27 | new_node.next = self.head |
| 28 | self.head.prev = new_node |
| 29 | self.head = new_node |
| 30 | new_node.prev = None |
| 31 | |
| 32 | #method to add an element in the last of the list i.e. tail |
| 33 | def addTail(self, x): |
| 34 | new_node = Node(x) |
| 35 | if (self.isEmpty()): |
| 36 | self.head = self.tail = new_node |
| 37 | new_node.next = None |
| 38 | return |
| 39 | self.tail.next = new_node |
| 40 | new_node.prev = self.tail |
| 41 | new_node.next = None |
| 42 | self.tail = new_node |
| 43 | |
| 44 | #method to insert an element at a specific position |
| 45 | def insert(self, x, pos): |
| 46 | new_node = Node(x) |
| 47 | temp = self.head |
| 48 | i = 1 |
| 49 | while i < pos-1: |
| 50 | temp = temp.next |
| 51 | i += 1 |
| 52 | new_node.prev = temp |
| 53 | new_node.next = temp.next |
| 54 | temp.next.prev = new_node |
| 55 | temp.next = new_node |
| 56 | |
| 57 | #method to remove the element at head |
| 58 | def removeHead(self): |
| 59 | temp = self.head |
| 60 | self.head = temp.next |
| 61 | temp.next.prev = None |
| 62 | temp = None |
| 63 | |
| 64 | #method to remove element at tail |
| 65 | def removeTail(self): |