5c9079a410
Manually merging: - README.md: I added the description from universe/README.md into the heading of dotfiles/README.md. - .envrc: dotfiles/.envrc was a superset of universe/.envrc - .gitignore: Adding some of the ignored patterns from universe/.gitignore to dotfiles/.gitignore Everything else here should be a simple rename.
56 lines
1.6 KiB
Python
56 lines
1.6 KiB
Python
import unittest
|
|
|
|
|
|
################################################################################
|
|
# Solution
|
|
################################################################################
|
|
def find_duplicate(xs):
|
|
self_ref_count = 0
|
|
for i in range(len(xs)):
|
|
if xs[i] == i + 1:
|
|
self_ref_count += 1
|
|
hops = len(xs) - 1 - self_ref_count
|
|
current = xs[-1]
|
|
while hops > 0:
|
|
current = xs[current - 1]
|
|
hops -= 1
|
|
return current
|
|
|
|
|
|
################################################################################
|
|
# Tests
|
|
################################################################################
|
|
class Test(unittest.TestCase):
|
|
# TODO: Debug why this fails.
|
|
def test_darren_from_interview_cake(self):
|
|
actual = find_duplicate([4, 1, 8, 3, 2, 7, 6, 5, 4])
|
|
expected = 4
|
|
self.assertEqual(actual, expected)
|
|
|
|
def test_just_the_repeated_number(self):
|
|
actual = find_duplicate([1, 1])
|
|
expected = 1
|
|
self.assertEqual(actual, expected)
|
|
|
|
def test_short_list(self):
|
|
actual = find_duplicate([1, 2, 3, 2])
|
|
expected = 2
|
|
self.assertEqual(actual, expected)
|
|
|
|
def test_last_cycle(self):
|
|
actual = find_duplicate([3, 4, 2, 3, 1, 5])
|
|
expected = 3
|
|
self.assertEqual(actual, expected)
|
|
|
|
def test_medium_list(self):
|
|
actual = find_duplicate([1, 2, 5, 5, 5, 5])
|
|
expected = 5
|
|
self.assertEqual(actual, expected)
|
|
|
|
def test_long_list(self):
|
|
actual = find_duplicate([4, 1, 4, 8, 3, 2, 7, 6, 5])
|
|
expected = 4
|
|
self.assertEqual(actual, expected)
|
|
|
|
|
|
unittest.main(verbosity=2)
|