def test_kth_to_last(self):
# Positive tests.
lst = SinglyLinkedList()
n = 4
for i in range(n):
lst.insert_tail(Node(i))
for k in range(n):
self.assertEqual(kth_to_last(lst, k).data, n - k - 1)
# Negative tests.
lst = SinglyLinkedList()
n = 4
for i in range(n):
lst.insert_tail(Node(i))
k = -1
self.assertEqual(kth_to_last(lst, k), None)
k = n
self.assertEqual(kth_to_last(lst, k), None)
def convert_array_to_singly_linked_list(elems: list[any]) -> SinglyLinkedList:
res = SinglyLinkedList()
for elem in elems:
res.insert_tail(elem)
return res
def test_remove_dups(self):
# Check removing dups from the empty list.
lst = SinglyLinkedList()
remove_dups(lst)
self.assertEqual(lst.size, 0)
# Check removing dups from the list wiht one element in it.
lst = SinglyLinkedList()
lst.insert_tail(Node(1))
remove_dups(lst)
self.assertEqual(lst.size, 1)
self.assertEqual(lst.head.data, 1)
# Check removing dups from the tree with repeated element in it.
lst = SinglyLinkedList()
original_data = [1, 1]
for i in range(len(original_data)):
lst.insert_tail(Node(original_data[i]))
remove_dups(lst)
self.assertEqual(lst.size, 1)
self.assertEqual(lst.head.data, 1)
lst = SinglyLinkedList()
original_data = [1, 1, 1, 1, 1]
for i in range(len(original_data)):
lst.insert_tail(Node(original_data[i]))
remove_dups(lst)
self.assertEqual(lst.size, 1)
self.assertEqual(lst.head.data, 1)
# Check removing dups from the tree with mixed data.
lst = SinglyLinkedList()
original_data = [1, 5, 3, 5, 4, 8, 1, 12, 33, 5]
expected_data = [1, 5, 3, 4, 8, 12, 33]
for i in range(len(original_data)):
lst.insert_tail(Node(original_data[i]))
remove_dups(lst)
self.assertEqual(lst.size, len(expected_data))
node = lst.head
for i in range(len(expected_data)):
self.assertEqual(node.data, expected_data[i])
node = node.next
lst = SinglyLinkedList()
original_data = [38, 49, 51, 1080, 12, -48, -48, 1080]
expected_data = [38, 49, 51, 1080, 12, -48]
for i in range(len(original_data)):
lst.insert_tail(Node(original_data[i]))
remove_dups(lst)
self.assertEqual(lst.size, len(expected_data))
node = lst.head
for i in range(len(expected_data)):
self.assertEqual(node.data, expected_data[i])
node = node.next
# Check removing dups from the tree with no repeated data.
lst = SinglyLinkedList()
original_data = [1, 2, 3, 4, 5]
expected_data = [1, 2, 3, 4, 5]
for i in range(len(original_data)):
lst.insert_tail(Node(original_data[i]))
remove_dups(lst)
self.assertEqual(lst.size, len(expected_data))
node = lst.head
for i in range(len(expected_data)):
self.assertEqual(node.data, expected_data[i])
node = node.next