def test_peek_last(self):
llist = SinglyLinkedList()
self.assertRaises(Exception, llist.peek_last)
llist.insert_first(0)
self.assertEqual(llist.peek_last(), 0)
llist.insert_first(-1)
self.assertEqual(llist.peek_last(), 0)
def test_clear(self):
llist = SinglyLinkedList()
llist.insert_first(0)
self.assertEqual(llist.size, 1)
self.assertEqual(llist.head.data, 0)
llist.clear()
self.assertEqual(llist.size, 0)
self.assertEqual(llist.head, None)
def test_insert_first(self):
llist = SinglyLinkedList()
llist.insert_first(1)
self.assertEqual(llist.size, 1)
self.assertEqual(llist.head.data, 1)
llist.insert_first(0)
self.assertEqual(llist.size, 2)
self.assertEqual(llist.head.data, 0)
self.assertEqual(llist.head.next.data, 1)
def test_is_empty(self):
llist = SinglyLinkedList()
self.assertTrue(llist.is_empty())
llist.insert_first(0)
self.assertFalse(llist.is_empty())
def test_contains(self):
llist = SinglyLinkedList()
llist.insert_first(0)
self.assertTrue(llist.contains(0))
self.assertFalse(llist.contains(1))
from singly_linked_list import SinglyLinkedList
def kth_to_last(k, singly_linked_list: SinglyLinkedList):
kth = singly_linked_list._head
end = singly_linked_list._head
counter = 0
while end is not None:
if counter >= k:
kth = kth._next
end = end._next
counter += 1
return kth
l = SinglyLinkedList()
l.insert_first(1)
l.insert_first(2)
l.insert_first(3)
l.insert_first(1)
l.insert_first(3)
l.insert_first(4)
l.insert_first(1)
l.insert_first(1)
print(l)
print(kth_to_last(6, l))
print(l)
i = 1