tvl-depot/deepmind/part_one/reverse-linked-list.py
William Carroll 5df3bb4e40 Partition deepmind directory into two parts
Since I did not pass my one-site interview with DM, but I have been invited to
attempt again, I decided to partition this directory into two parts:
1. part_one: Hosting the exercises that I completed before my first attempt at
   earning the job.
2. part_two: Hosting the exercise that I will complete before my second attempt
   at earning the job.
2020-02-06 16:56:06 +00:00

74 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)