class TestIntersection(unittest.TestCase):
def setUp(self):
# Case without intersection
self.a = SinglyLinkedList()
self.b = SinglyLinkedList()
self.b.append(1)
self.b.append(2)
# Case with intersection
self.n1 = Node(1)
self.n2 = Node(2)
self.n1.next = self.n2
self.c = SinglyLinkedList()
self.c.append('not a match')
self.c.head.next = self.n1
self.d = SinglyLinkedList()
self.d.head = self.n1
def test_intersection(self):
self.assertIsNone(intersection(self.a, self.b)) # no intersection
self.assertEqual(intersection(self.c, self.d), self.n1) # intersection
def test_intersection_fast(self):
self.assertIsNone(intersection_fast(self.a, self.b)) # no intersection
self.assertEqual(intersection_fast(self.c, self.d),
self.n1) # intersection
def sum_lists_reverse(*args):
"""
Sums singly linked lists. Each node is a digit stored in reverse order.
:param args: SinglyLinkedLists to be summed.
:return SinglyLinkedList: sum of inputs
"""
sum_list = SinglyLinkedList()
nodes = list(map(lambda x: x.head, args)) # head node of each SinglyLinkedList
carryover = 0
while True:
# Sum data from each list
summation = carryover
for i, node in enumerate(nodes):
if node is None:
continue
summation += node.data
nodes[i] = node.next
# Account for addition carryover
carryover, summation = divmod(summation, 10)
sum_list.append(summation)
# Check for end of all lists
if all(map(lambda x: x is None, nodes)) and carryover == 0:
break
return sum_list
def sum_lists_forward(*args):
"""
Sums singly linked lists. Each node is a digit stored in forward order.
:param args: SinglyLinkedLists to be summed.
:return SinglyLinkedList: sum of inputs
"""
#TODO: move some of this logic to other functions. Too wordy / complex.
sum_list = SinglyLinkedList()
# pad lists
lengths = list(map(len, args))
max_length = max(lengths)
for i, arg in enumerate(args):
pad_linked_list(arg, max_length - lengths[i])
# sum lists
nodes = list(map(lambda x: x.head, args))
while True:
# Sum data from each list
summation = 0
for i, node in enumerate(nodes):
summation += node.data
nodes[i] = node.next
sum_list.append(summation)
# Check if the end of a list is reached (all lists are the same length)
if node.next is None:
break
# account for carryover
while True:
exit_flag = True
runner = sum_list.head
while runner.next is not None:
carry, keep = divmod(runner.next.data, 10)
runner.data += carry
runner.next.data = keep
runner = runner.next
if carry > 0:
exit_flag = False
# check that head value isn't >=10
carry, keep = divmod(sum_list.head.data, 10)
if carry > 0:
sum_list.head.data = keep
pad_linked_list(sum_list, 1, value=carry)
exit_flag = False
if exit_flag:
break
return sum_list
def setUp(self):
# setUp for remove_dups:
#
# SinglyLinkedList with duplicates
self.sll = SinglyLinkedList()
linked_list_data = [1, 1, 2, 3, 2, 3, ['abc'], ['abc']]
for data in linked_list_data:
self.sll.append(data)
# Solution (duplicates removed)
self.sll_solution = SinglyLinkedList() # solution for non-hashable case
linked_list_solution_data = [1, 2, 3, ['abc']]
for data in linked_list_solution_data:
self.sll_solution.append(data)
# setUp for remove_dups_hashable:
#
# SinglyLinkedList with hashable data
self.sll_hashable = SinglyLinkedList()
hashable_linked_list_data = [1, 1, 2, 3, 2, 3, ('abc', 'def'), ('abc', 'def')]
for data in hashable_linked_list_data:
self.sll_hashable.append(data)
# Hashable solution (duplicates removed)
self.sll_hashable_solution = SinglyLinkedList() # solution for non-hashable case
linked_list_solution_data = [1, 2, 3, ('abc', 'def')]
for data in linked_list_solution_data:
self.sll_hashable_solution.append(data)
def setUp(self):
# No loop
self.a = SinglyLinkedList()
self.a.append(1)
self.a.append(2)
self.a.append(3)
# Empty list (no loop)
self.b = SinglyLinkedList()
# Loop
self.c = SinglyLinkedList()
self.n1 = Node(1)
self.n2 = Node(2)
self.n3 = Node(3)
self.n1.next = self.n2
self.n2.next = self.n3
self.n3.next = self.n1
self.c.append('not part of loop')
self.c.append('also not part of loop')
self.c.head.next.next = self.n1
def test_k_to_last(self):
# Create SinglyLinkedList
sll = SinglyLinkedList()
sll.append(1)
sll.append(2)
sll.append(3)
sll.append(4)
# Find last element
data = k_to_last(sll, 1)
self.assertEqual(data, 4)
# Find 2nd to last element
data = k_to_last(sll, 2)
self.assertEqual(data, 3)
# Find first element
data = k_to_last(sll, 4)
self.assertEqual(data, 1)
# Check if it raises ValueError when k > len(sll)
self.assertRaises(ValueError, k_to_last, sll, 10)
# Check if it raises ValueError when k = 0
self.assertRaises(ValueError, k_to_last, sll, 0)
def test_partition(self):
# Create SinglyLinkedList
sll = SinglyLinkedList()
for i in [3, 5, 8, 5, 10, 2, 1]:
sll.append(i)
# Solution
solution = SinglyLinkedList()
for i in [3, 2, 1, 5, 8, 5, 10]:
solution.append(i)
# Check if partition produces the solution
partition(sll, 5)
self.assertEqual(solution, sll)
class TestRemoveDups(unittest.TestCase):
def setUp(self):
# setUp for remove_dups:
#
# SinglyLinkedList with duplicates
self.sll = SinglyLinkedList()
linked_list_data = [1, 1, 2, 3, 2, 3, ['abc'], ['abc']]
for data in linked_list_data:
self.sll.append(data)
# Solution (duplicates removed)
self.sll_solution = SinglyLinkedList() # solution for non-hashable case
linked_list_solution_data = [1, 2, 3, ['abc']]
for data in linked_list_solution_data:
self.sll_solution.append(data)
# setUp for remove_dups_hashable:
#
# SinglyLinkedList with hashable data
self.sll_hashable = SinglyLinkedList()
hashable_linked_list_data = [1, 1, 2, 3, 2, 3, ('abc', 'def'), ('abc', 'def')]
for data in hashable_linked_list_data:
self.sll_hashable.append(data)
# Hashable solution (duplicates removed)
self.sll_hashable_solution = SinglyLinkedList() # solution for non-hashable case
linked_list_solution_data = [1, 2, 3, ('abc', 'def')]
for data in linked_list_solution_data:
self.sll_hashable_solution.append(data)
def test_remove_dups(self):
# Test remove_dups function
self.assertNotEqual(self.sll, self.sll_solution)
remove_dups(self.sll)
self.assertEqual(self.sll, self.sll_solution)
def test_remove_dups_hashable(self):
# Test remove_dups hashable function
# Requires hashable data
self.assertNotEqual(self.sll_hashable, self.sll_hashable_solution)
remove_dups_hashable(self.sll_hashable)
self.assertEqual(self.sll_hashable, self.sll_hashable_solution)
class TestLoopDetection(unittest.TestCase):
def setUp(self):
# No loop
self.a = SinglyLinkedList()
self.a.append(1)
self.a.append(2)
self.a.append(3)
# Empty list (no loop)
self.b = SinglyLinkedList()
# Loop
self.c = SinglyLinkedList()
self.n1 = Node(1)
self.n2 = Node(2)
self.n3 = Node(3)
self.n1.next = self.n2
self.n2.next = self.n3
self.n3.next = self.n1
self.c.append('not part of loop')
self.c.append('also not part of loop')
self.c.head.next.next = self.n1
def test_loop_detection(self):
# No loop
self.assertIsNone(loop_detection(self.a))
# Empty list (no loop)
self.assertIsNone(loop_detection(self.b))
# Loop
self.assertIs(loop_detection(self.c), self.n1)
def test_loop_detection_fast(self):
# No loop
self.assertIsNone(loop_detection_fast(self.a))
# Empty list (no loop)
self.assertIsNone(loop_detection_fast(self.b))
# Loop
self.assertIs(loop_detection_fast(self.c), self.n1)
def setUp(self):
# Case without intersection
self.a = SinglyLinkedList()
self.b = SinglyLinkedList()
self.b.append(1)
self.b.append(2)
# Case with intersection
self.n1 = Node(1)
self.n2 = Node(2)
self.n1.next = self.n2
self.c = SinglyLinkedList()
self.c.append('not a match')
self.c.head.next = self.n1
self.d = SinglyLinkedList()
self.d.head = self.n1
def test_delete_middle_node(self):
# Create SinglyLinkedList
sll = SinglyLinkedList()
sll.append(1)
sll.append(2)
sll.append(3)
sll.append(4)
# Solution
solution = SinglyLinkedList()
solution.append(1)
solution.append(3)
solution.append(4)
# Check if delete_middle_node produces the solution
node = sll.head.next # node 2
delete_middle_node(node)
self.assertEqual(solution, sll)
def test_palindrome(self):
# Case 1: (1, 2, 3, 2, 1) = Palindrome (True)
p = SinglyLinkedList()
p.append(1)
p.append(2)
p.append(3)
p.append(2)
p.append(1)
self.assertTrue(palindrome(p))
# Case 2: (1) = Palindrome (True)
p = SinglyLinkedList()
p.append(1)
self.assertTrue(palindrome(p))
# Case 3: (9, 9) = Palindrome (True)
p = SinglyLinkedList()
p.append(9)
p.append(9)
self.assertTrue(palindrome(p))
# Case 4: ('a', 'b', 'c', 'a') != Palindrome (False)
p = SinglyLinkedList()
p.append('a')
p.append('b')
p.append('c')
p.append('a')
self.assertTrue(palindrome(p))
# Case 5 (empty case): () = Palindrome (True)
self.assertTrue(palindrome(SinglyLinkedList()))