def merge(a, b):
'''
Merges two linked list sorting data in the nodes
Returns a list_merged linked list
'''
list_merged = SinglyLinkedList()
list_merged.prepend(Node(
0)) # Add a fake head that is discarted later to avoid empty lists
current = list_merged.head
a_head = a.head
b_head = b.head
# Iterate over each node until we reach the tail one and build the list by updating the current next node
while a_head != None or b_head != None:
if a_head is None:
current.next = b_head
b_head = b_head.next
elif b_head is None:
current.next = a_head
a_head = a_head.next
else:
if a_head.data < b_head.data:
current.next = a_head
a_head = a_head.next
else:
current.next = b_head
b_head = b_head.next
current = current.next
# Discard fake head and set first list_merged node as head
list_merged.head = list_merged.head.next
return list_merged
class SetupSinglyLinkedList:
def setup_method(self):
self.test_list = SinglyLinkedList()
self.test_list.append(42)
self.test_list.append(33)
self.test_list.append('spam')
self.test_list.prepend([])
self.test_list.prepend({'a': 42})
def palindromic(l):
r = SinglyLinkedList()
current = l.head
while current is not None:
r.prepend(SinglyLinkedNode(current.value))
current = current.child
l_iter = l.head
r_iter = r.head
while l_iter is not None:
if l_iter.value != r_iter.value:
return False
l_iter = l_iter.child
r_iter = r_iter.child
return True
def palindromic(l):
r = SinglyLinkedList()
current = l.head
while current is not None:
r.prepend(SinglyLinkedNode(current.value))
current = current.child
l_iter = l.head
r_iter = r.head
while l_iter is not None:
if l_iter.value != r_iter.value:
return False
l_iter = l_iter.child
r_iter = r_iter.child
return True
def create_list(self, length_neck, length_loop):
neck = SinglyLinkedList()
for i in range(length_neck):
neck.prepend(SinglyLinkedNode(length_neck - i))
loop = SinglyLinkedList()
for i in range(length_loop):
loop.prepend(SinglyLinkedNode(length_neck + length_loop - i))
if loop.head is not None:
end = loop.head
while end.child is not None:
end = end.child
end.child = loop.head
neck.append(loop.head)
return neck
def create_list(self, length_neck, length_loop):
neck = SinglyLinkedList()
for i in range(length_neck):
neck.prepend(SinglyLinkedNode(length_neck - i))
loop = SinglyLinkedList()
for i in range(length_loop):
loop.prepend(SinglyLinkedNode(length_neck + length_loop - i))
if loop.head is not None:
end = loop.head
while end.child is not None:
end = end.child
end.child = loop.head
neck.append(loop.head)
return neck
def test_linked_list_single_item():
"""test_linked_list_single_item."""
ll = SinglyLinkedList()
ll.prepend(5)
assert ll.head.item is 5
print("One item, ", ll)
for node in ll:
assert node.item is 5
assert 5 in ll
assert not any(value in ll for value in range(-100, 100) if value is not 5)
assert len(ll) is 1
assert ll.remove(5) is 5
assert 5 not in ll
assert len(ll) is 0
for _ in ll:
raise AssertionError("Collection should be empty, iterator returned.")
print("Passed all tests for single item in linked list")
def time_prepend():
n = 50000
print('time_prepend, n =', n)
with timewith(' linked list '):
container = SLL()
for x in range(n):
container.prepend(x)
del container
with timewith(' list '):
container = list()
for x in range(n):
container.insert(0, x)
del container
with timewith(' deque '):
container = deque()
for x in range(n):
container.appendleft(x)
del container
def test_linked_list_many_items():
"""test_linked_list_many_items."""
ll = SinglyLinkedList()
numbers = [value for value in range(-100, 100)]
for number in numbers:
ll.prepend(number)
print("Many items, ", ll)
assert len(ll) == len(numbers)
assert [node.item for node in ll] == numbers[-1::-1]
assert all(number in ll for number in numbers)
assert not any(
number in ll for number in chain(range(-200, -100), range(100, 200)))
assert ll.remove(500) is None
assert all(ll.remove(value) is not None for value in numbers)
assert not any(number in ll for number in numbers)
assert len(ll) is 0
for _ in ll:
raise AssertionError("Collection should be empty, iterator returned.")
print("Passed all tests for single item in linked list")
def build_list_from_string(self, s):
l = SinglyLinkedList()
for c in s[::-1]:
l.prepend(SinglyLinkedNode(c))
return l
def build_list_from_string(self, s):
l = SinglyLinkedList()
for c in s[::-1]:
l.prepend(SinglyLinkedNode(c))
return l
def build_list(self, values):
l = SinglyLinkedList()
for value in values[::-1]:
l.prepend(SinglyLinkedNode(value))
return l
def test_prepend_adds_an_element_at_the_beginning_even_without_a_first_node(
self):
linked = SinglyLinkedList()
linked.prepend(1000)
self.assertEqual(linked.as_list(), [1000])
def test_prepend_adds_an_element_at_the_beginning(self):
linked = SinglyLinkedList(100)
linked.prepend(1000)
self.assertEqual(linked.as_list(), [1000, 100])
elif b_head is None:
current.next = a_head
a_head = a_head.next
else:
if a_head.data < b_head.data:
current.next = a_head
a_head = a_head.next
else:
current.next = b_head
b_head = b_head.next
current = current.next
# Discard fake head and set first list_merged node as head
list_merged.head = list_merged.head.next
return list_merged
N1 = Node(10)
N2 = Node(20)
N3 = Node(30)
N4 = Node(40)
N5 = Node(50)
list = SinglyLinkedList(N1)
list.prepend(N2)
list.prepend(N3)
list.prepend(N4)
list.prepend(N5)
print('Original', list)
print('Sorted', merge_sort(list))
def build_list(self, values):
l = SinglyLinkedList()
for value in values[::-1]:
l.prepend(SinglyLinkedNode(value))
return l
def list_rep(self, a_string):
a = SinglyLinkedList()
for digit in a_string:
a.prepend(SinglyLinkedNode(int(digit)))
return a
def list_rep(self, a_string):
a = SinglyLinkedList()
for digit in a_string:
a.prepend(SinglyLinkedNode(int(digit)))
return a
