def append(self, item, number_of_columns=0):
"""Insert the given item at the tail of this linked list.
TODO: Running time: O(1) Why and under what conditions?"""
# TODO: Create new node to hold given item
node = Node(item)
if type(item) is list:
node.data = LinkedList(node.data)
# TODO: Append node after tail, if it exists
if self.tail is None:
self.head = node
self.tail = node
else:
self.tail.next = node
self.tail = node
else:
# start from first column
columns = 0
for node in self:
if columns == number_of_columns:
linkedlist = node.data
linkedlist.append(item)
break
else:
# count columns
columns += 1
def prepend(self, item, number_of_columns):
"""Insert the given item at the head of this linked list.
TODO: Running time: O(1) Why and under what conditions?"""
# TODO: Create new node to hold given item
node = Node(item)
if type(item) is list:
node.data = LinkedList(node.data)
# TODO: Prepend node before head, if it exists
if self.is_empty():
self.head = node
self.tail = node
else:
node.next = self.head
self.head = node
else:
columns = 0
for node in self:
if columns == number_of_columns:
linkedlist = node.data
linkedlist.prepend(item)
break
else:
# count columns
columns += 1
