def rev_num_items_in_list(self, number_items_to_reverse):
if number_items_to_reverse >= self.count:
return False
stack = LinkedStack()
node = self.head
for i in range(0, number_items_to_reverse):
stack.push(node.value)
if node.next is not None:
node = node.next
rest_of_list = node
print("Stack: ")
stack.print_list()
self.head = None
prev = None
while True:
new_node = LinkedListNode(stack.pop())
if self.head is None:
self.head = new_node
prev = new_node
else:
prev.next = new_node
new_node.prev = prev
prev = new_node
if stack.is_empty():
break
prev.next = rest_of_list
rest_of_list.prev = prev
return True
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.head.prev = new_node
else:
self.tail = new_node
self.head = new_node
self.count += 1
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
self.tail = new_node
return
new_node.prev = self.tail
self.tail.next = new_node
self.tail = new_node
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_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