def to_linked_list(values: list) -> ListNode:
if values:
head = ListNode(values[0])
current_node = head
for i in values[1:]:
current_node.next = ListNode(i)
current_node = current_node.next
return head
else:
return None
def remove_dupes(head: ListNode) -> ListNode:
if head:
node = ListNode(head.val)
head = head.next
else:
return ListNode("")
new_head = node
while head:
if head.val != node.val:
node.next = ListNode(head.val)
node = node.next
head = head.next
return new_head
def remove_linked_list_val(head: ListNode, val: int) -> ListNode:
if head is None:
return head
start = head
previous = None
while start:
if start.val == val:
if previous is None: # Start of list
head = head.next
start = head
else:
if not start.next: # End of list
previous.next = None
break
else:
start = start.next
previous.next = start
else:
previous = start
start = start.next
print(previous.val, start.val)
if not head:
return ListNode(None)
return head
def merge_sorted_lists(l1: ListNode, l2: ListNode) -> ListNode:
def to_list(head: ListNode) -> list:
output = list()
while head:
output.append(head.val)
head = head.next
return output
def to_linked_list(values: list) -> ListNode:
if values:
head = ListNode(values[0])
current_node = head
for i in values[1:]:
current_node.next = ListNode(i)
current_node = current_node.next
return head
else:
return None
linked_list_values = list()
for i in to_list(l1) + to_list(l2):
if i is not None:
linked_list_values.append(i)
if linked_list_values != []:
linked_list_values.sort()
return to_linked_list(linked_list_values)
else:
return ListNode('')
def remove_linked_list_val_messy(head: ListNode, val: int) -> ListNode:
if not head.next: # Len = 1 or empty list edge case
if head.val != val:
return head
else:
return ListNode(None)
while head.val == val: # First list node to be removed edge case
if head.next:
head = head.next
else:
return ListNode(None)
slow = head
fast = head.next
while fast.next:
print(slow.val, fast.val)
if fast.val == val:
slow.next = slow.next.next
slow = slow.next
fast = fast.next.next
else:
slow = slow.next
fast = fast.next
if not fast.next:
if fast.val == val:
slow.next = None
break
if fast.val == val: # Two item list with last val match edge case
slow.next = None
print(head.to_list())
return head
def remove_nth_node_from_end(head: ListNode, n: int) -> ListNode:
slow = head
fast = head
for _ in range(n):
fast = fast.next
if not fast: # n = first item edge case
head = slow.next
if not head: # list of one item edge case
head = ListNode("")
return head
while fast.next is not None:
fast = fast.next
slow = slow.next
slow.next = slow.next.next
return head
def test_3204_true(self):
input = has_cycle(ListNode.build_circular([3, 2, 0, -4]))
self.assertTrue(input)
def test_blank(self):
input = remove_dupes(ListNode.build([]))
output = ListNode.build([])
self.assertEqual(input, output)
def test_1234567888(self):
input = remove_dupes(ListNode.build([1, 2, 3, 4, 5, 6, 7, 8, 8, 8]))
output = ListNode.build([1, 2, 3, 4, 5, 6, 7, 8])
self.assertEqual(input, output)
def test_11112233(self):
input = remove_dupes(ListNode.build([0, 11, 11, 22, 33]))
output = ListNode.build([0, 11, 22, 33])
self.assertEqual(input, output)
def test_1_1(self): # Test works on LeetCode, but not here
input = remove_nth_node_from_end(ListNode.build([1]), 1)
output = ListNode.build("")
self.assertEqual(input, output)
def test_12345678_false(self):
input = has_cycle(ListNode.build([1, 2, 3, 4, 5, 6, 7, 8]))
self.assertFalse(input)
def test_1263456_6(self):
input = remove_linked_list_val(ListNode.build([1, 2, 6, 3, 4, 5, 6]),
6)
self.assertEqual(input, ListNode.build([1, 2, 3, 4, 5]))
def del_node(node: ListNode):
while node.next.next:
node.val = node.next.val
node = node.next
node.val = node.next.val
node.next = None
def test_45_4(self):
head = ListNode.build([4, 5])
node = head
del_node(node)
out_list = ListNode.build([5])
self.assertEqual(head, out_list)
def test_4519_1(self):
head = ListNode.build([4, 5, 1, 9])
node = head.next.next
del_node(node)
out_list = ListNode.build([4, 5, 9])
self.assertEqual(head, out_list)
def test_123456789_9(self):
input = remove_nth_node_from_end(
ListNode.build([1, 2, 3, 4, 5, 6, 7, 8, 9]), 9)
output = ListNode.build([2, 3, 4, 5, 6, 7, 8, 9])
self.assertEqual(input, output)
def test_123_3(self):
input = remove_nth_node_from_end(ListNode.build([1, 2, 3]), 3)
output = ListNode.build([2, 3])
self.assertEqual(input, output)
def test_12_true(self):
input = has_cycle(ListNode.build_circular([1, 2]))
self.assertTrue(input)
def test_81632_519100(self):
list1 = ListNode.build([8, 16, 32])
list2 = ListNode.build([5, 19, 100])
input = merge_sorted_lists(list1, list2)
output = ListNode.build([5, 8, 16, 19, 32, 100])
self.assertEqual(input, output)
def test_blank_false(self):
input = has_cycle(ListNode.build([]))
self.assertFalse(input)
def test_uneven_lists(self):
list1 = ListNode.build([1, 2, 3, 4])
list2 = ListNode.build([-99, 4, 32])
input = merge_sorted_lists(list1, list2)
output = ListNode.build([-99, 1, 2, 3, 4, 4, 32])
self.assertEqual(input, output)
def test_12345(self):
head = ListNode.build([1, 2, 3, 4, 5])
reversed = ListNode.build([5, 4, 3, 2, 1])
self.assertEqual(reverse_ll(head), reversed)
def test_12_2(self):
input = remove_nth_node_from_end(ListNode.build([1, 2]), 2)
output = ListNode.build([2])
self.assertEqual(input, output)
def test_124_134(self):
list1 = ListNode.build([1, 2, 4])
list2 = ListNode.build([1, 3, 4])
input = merge_sorted_lists(list1, list2)
output = ListNode.build([1, 1, 2, 3, 4, 4])
self.assertEqual(input, output)
def test_blank(self):
head = ListNode.build([])
reversed = ListNode.build([])
self.assertEqual(reverse_ll(head), reversed)
def test_minus1248_minus6945(self):
list1 = ListNode.build([-12, 4, 8])
list2 = ListNode.build([-6, 9, 45])
input = merge_sorted_lists(list1, list2)
output = ListNode.build([-12, -6, 4, 8, 9, 45])
self.assertEqual(input, output)
def test_112(self):
input = remove_dupes(ListNode.build([1, 1, 2]))
output = ListNode.build([1, 2])
self.assertEqual(input, output)
def test_blank_lists(self):
list1 = ListNode.build([])
list2 = ListNode.build([])
input = merge_sorted_lists(list1, list2)
output = ListNode('')
self.assertEqual(input, output)
def test_short_true(self):
head = ListNode.build([1, 2, 2, 1])
self.assertTrue(is_palindrome(head))
