def insert_at_position(self, position, data):
""" Position is 1 based. """
if self.head is None:
raise EmptyListError("List is empty, can't insert.")
list_length = self.get_length()
if not (1 <= position <= list_length + 1):
raise RangeError(
"Position range must be 1 through {0}.".format(list_length +
1))
if position == 1:
self.insert_at_beginning(data)
elif position == list_length + 1:
self.insert_at_end(data)
else:
pointer = self.head
pos = 1
while pos != position - 1:
pointer = pointer.get_next()
pos += 1
node = NodeCircular(data)
node.set_next(pointer.get_next())
pointer.set_next(node)
def nth_node_from_end(linked_list, n):
"""
Find nth node from end of a linked list (assume positions as 1 based).
Hint: For a linked list of size m, nth node from end would be
(m - n + 1)th node from beginning.
:param SingleLinkedList linked_list: The linked list to operate.
:param int n: The position from end.
:return: the data of the node.
:rtype: int
:raises EmptyListError: if the list is empty.
:raises RangeError: if length of list < n < 0.
"""
list_length = linked_list.get_length()
if list_length == 0:
raise EmptyListError("List is empty, can't find node")
if not (1 <= n <= list_length):
raise RangeError("Position range must be 1 through {0}".format(list_length))
nth_from_end = list_length - n + 1
pointer = linked_list.head
position = 1
while position != nth_from_end:
pointer = pointer.get_next()
position += 1
return pointer.data
def delete_at_position(self, position):
""" Position is 1 based. """
if self.head is None:
raise EmptyListError("List is empty, can't delete.")
list_length = self.get_length()
if not (1 <= position <= list_length):
raise RangeError(
"Position range must be 1 through {0}.".format(list_length))
if position == 1:
self.delete_at_beginning()
else:
pointer = self.head
pos = 1
while pos != position - 1:
pointer = pointer.get_next()
pos += 1
next = pointer.get_next().get_next()
pointer.get_next().set_next(None)
pointer.set_next(next)