def test_reverse(self):
dll = LinkedList()
items = 100
assert dll.is_empty()
assert dll.reverse() is None
assert dll.is_empty()
for i in range(items):
assert dll.append(i) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.tail, Node)
assert dll.size == items
assert dll.head is not dll.tail
assert dll.head.data == 0
assert dll.head.prev is None
assert dll.tail.data == items - 1
assert dll.tail.next is None
assert dll.reverse() is None
assert isinstance(dll.head, Node)
assert isinstance(dll.tail, Node)
assert dll.size == items
assert dll.head is not dll.tail
assert dll.head.data == items - 1
assert dll.head.prev is None
assert dll.tail.data == 0
assert dll.tail.next is None
match = items - 1
for node in dll:
assert node.data == match
match -= 1
assert dll.reverse() is None
match = 0
for node in dll:
assert node.data == match
match += 1
def test_sublist_halves(self):
dll = LinkedList()
items = 10
assert dll.head is None
assert dll.size == 0
for i in range(items):
assert dll.push(i) is None
dll.reverse()
def halves(linked_list, begin, end):
mid = linked_list.size // 2
left = sublist(linked_list, begin, mid)
right = sublist(linked_list, mid, end)
return left, right
def print_list(linked_list):
for node in linked_list:
print(node.data, end=',')
print(" ")
def check(linked_list):
if linked_list.size <= 2:
return
left, right = halves(linked_list, 0, linked_list.size)
if linked_list.size % 2: # Odds
assert left.size == (linked_list.size // 2)
assert right.size == (linked_list.size // 2 + 1)
else: # Evens
assert left.size == (linked_list.size // 2)
assert right.size == (linked_list.size // 2)
print_list(left)
print_list(right)
check(left)
check(right)
check(dll)