def test_node_delete(self):
node_1 = Node(3)
node_2 = Node(4)
node_3 = Node(5)
node_1.next = node_2
node_2.next = node_3
node_2.prev = node_1
node_3.prev = node_2
node_2.delete()
self.assertEqual(node_1.next, node_3)
self.assertEqual(node_3.prev, node_1)
def insert_at_beginning(head, data):
temp = head
new_node = Node(data)
new_node.next = temp
temp.prev = new_node
head = new_node
return head
def clone_list(lst):
# step 1
# append new nodes after existing nodes
current = lst.head
while current:
current_next = current.next
new_node = Node(current.key, current.data + " :: new")
current.next = new_node
new_node.next = current_next
current = current_next
# step2
# assign random pointers
current = lst.head
while current:
if current.random:
current.next.random = current.random.next
current = current.next.next
# step 3
# seperate two lists
new_list = DoublyList()
new_head = lst.head.next
new_list.head = new_head
old = lst.head
new = new_head
while old:
old.next = new.next
old = old.next
new.next = old.next if old else None
new = new.next if new else None
return new_list
def test_has_next(self):
node = Node(1)
second_node = Node(2)
node.next = second_node
self.assertIs(node.next, second_node)
from doubly_linked_list import Node, DoublyLinkedList
if __name__ == '__main__':
llist = DoublyLinkedList()
llist.head = Node(1)
second = Node(2)
third = Node(4)
llist.head.next = second
second.next = third
llist.print_list()
llist.insert_after(2, 3)
print('\nInserting 3 after 2 ..')
llist.print_list()
llist.append(5)
print('\nAppending 5 ..')
llist.print_list()
llist.insert_before(2, 0)
print('\nInserting 0 before 2 ..')
llist.print_list()
llist.delete_node_position(4)
print('\nDeleting node at position 4 ..')
llist.print_list()
print('\nCount:', llist.get_count())
def addAtStart(self, value): tempNode = Node(value) self.head.prev = tempNode tempNode.next = self.head self.head = tempNode self.printList()
