75 lines
1.8 KiB
Python
75 lines
1.8 KiB
Python
|
import unittest
|
||
|
|
|
||
|
|
|
||
|
|
def reverse(node):
|
||
|
|
prev = None
|
||
|
|
next = None
|
||
|
|
curr = node
|
||
|
|
|
||
|
|
while curr:
|
||
|
|
next = curr.next
|
||
|
|
curr.next = prev
|
||
|
|
prev = curr
|
||
|
|
curr = next
|
||
|
|
|
||
|
|
return prev
|
||
|
|
|
||
|
|
|
||
|
|
# Tests
|
||
|
|
class Test(unittest.TestCase):
|
||
|
|
class LinkedListNode(object):
|
||
|
|
def __init__(self, value, next=None):
|
||
|
|
self.value = value
|
||
|
|
self.next = next
|
||
|
|
|
||
|
|
def get_values(self):
|
||
|
|
node = self
|
||
|
|
values = []
|
||
|
|
while node is not None:
|
||
|
|
values.append(node.value)
|
||
|
|
node = node.next
|
||
|
|
return values
|
||
|
|
|
||
|
|
def test_short_linked_list(self):
|
||
|
|
second = Test.LinkedListNode(2)
|
||
|
|
first = Test.LinkedListNode(1, second)
|
||
|
|
|
||
|
|
result = reverse(first)
|
||
|
|
self.assertIsNotNone(result)
|
||
|
|
|
||
|
|
actual = result.get_values()
|
||
|
|
expected = [2, 1]
|
||
|
|
self.assertEqual(actual, expected)
|
||
|
|
|
||
|
|
def test_long_linked_list(self):
|
||
|
|
sixth = Test.LinkedListNode(6)
|
||
|
|
fifth = Test.LinkedListNode(5, sixth)
|
||
|
|
fourth = Test.LinkedListNode(4, fifth)
|
||
|
|
third = Test.LinkedListNode(3, fourth)
|
||
|
|
second = Test.LinkedListNode(2, third)
|
||
|
|
first = Test.LinkedListNode(1, second)
|
||
|
|
|
||
|
|
result = reverse(first)
|
||
|
|
self.assertIsNotNone(result)
|
||
|
|
|
||
|
|
actual = result.get_values()
|
||
|
|
expected = [6, 5, 4, 3, 2, 1]
|
||
|
|
self.assertEqual(actual, expected)
|
||
|
|
|
||
|
|
def test_one_element_linked_list(self):
|
||
|
|
first = Test.LinkedListNode(1)
|
||
|
|
|
||
|
|
result = reverse(first)
|
||
|
|
self.assertIsNotNone(result)
|
||
|
|
|
||
|
|
actual = result.get_values()
|
||
|
|
expected = [1]
|
||
|
|
self.assertEqual(actual, expected)
|
||
|
|
|
||
|
|
def test_empty_linked_list(self):
|
||
|
|
result = reverse(None)
|
||
|
|
self.assertIsNone(result)
|
||
|
|
|
||
|
|
|
||
|
|
unittest.main(verbosity=2)
|