1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
|
import unittest
from math import floor
def midpoint(a, b):
return a + floor((b - a) / 2)
def do_find_rotation_point(a, b, xs):
i = midpoint(a, b)
count = b - a + 1
if count == 2:
if xs[a] > xs[b]:
return b
else:
return -1
if i in {a, b}:
return i
if xs[a] < xs[i]:
return do_find_rotation_point(i, b, xs)
else:
return do_find_rotation_point(a, i, xs)
def find_rotation_point(xs):
return do_find_rotation_point(0, len(xs) - 1, xs)
# Tests
class Test(unittest.TestCase):
def test_small_list(self):
actual = find_rotation_point(['cape', 'cake'])
expected = 1
self.assertEqual(actual, expected)
def test_medium_list(self):
actual = find_rotation_point(
['grape', 'orange', 'plum', 'radish', 'apple'])
expected = 4
self.assertEqual(actual, expected)
def test_large_list(self):
actual = find_rotation_point([
'ptolemaic', 'retrograde', 'supplant', 'undulate', 'xenoepist',
'asymptote', 'babka', 'banoffee', 'engender', 'karpatka',
'othellolagkage'
])
expected = 5
self.assertEqual(actual, expected)
unittest.main(verbosity=2)
|
