def add_item_at_index(self, index, data):
new_node = LinkedListNode(data)
self.count += 1
if self.head is None:
self.head = new_node
self.tail = new_node
return
node = self.head
prev = None
for i in range(0, index):
prev = node
node = node.next
if node is None:
break
if prev:
prev.next = new_node
new_node.prev = prev
else:
self.head.prev = new_node
new_node.next = self.head
self.head = new_node
if node:
node.prev = new_node
new_node.next = node
else:
self.tail = new_node
def add_item_top(self, data):
new_node = LinkedListNode(data)
if self.head is not None:
new_node.next = self.head
self.fix_tail(self.head, new_node)
else:
new_node.next = new_node
self.head = new_node
self.count += 1
def add_item_bottom(self, data):
new_node = LinkedListNode(data)
self.count += 1
if self.head is None:
self.head = new_node
new_node.next = self.head
return
node = self.head
while node.next is not self.head:
node = node.next
node.next = new_node
new_node.next = self.head
def add_item_top(self, data):
new_node = LinkedListNode(data)
if self.head is not None:
new_node.next = self.head
self.head.prev = new_node
else:
self.tail = new_node
self.head = new_node
self.count += 1
def add_item_at_index(self, index, data):
new_node = LinkedListNode(data)
self.count += 1
if self.head is None:
self.head = new_node
new_node.next = self.head
return
node = self.head
prev = None
for i in range(0, index):
prev = node
node = node.next
#in the case of being at the bottom of the list we want prev to be the last element, so node will be head.
if node == self.head:
break
if prev:
prev.next = new_node
else:
self.fix_tail(self.head, new_node)
self.head = new_node
if node != self.head:
new_node.next = node
else:
new_node.next = self.head
def push(self, data):
node = LinkedListNode(data)
if self.head:
node.next = self.head
self.head = node
self.num_items += 1