tvl-depot/data_structures_and_algorithms/nth-fibonacci.py
William Carroll d4d8397e5f Add InterviewCake.com examples
Adds some of the code I generated while studying for a role transfer at Google
using the fantastic resource, InterviewCake.com. This work predates the
mono-repo.

I should think of ways to DRY up this code and the code in
crack_the_coding_interview, but I'm afraid I'm creating unnecessary work for
myself that way.
2020-01-15 14:25:33 +00:00

59 lines
1.5 KiB
Python

import unittest
################################################################################
# Solution
################################################################################
def fib(n):
"""This should be accomplishable in O(1) space."""
if n in {0, 1}:
return n
a = 0 # i = 0
b = 1 # i = 1
for x in range(2, n + 1):
result = a + b
a = b
b = result
return result
################################################################################
# Tests
################################################################################
class Test(unittest.TestCase):
def test_zeroth_fibonacci(self):
actual = fib(0)
expected = 0
self.assertEqual(actual, expected)
def test_first_fibonacci(self):
actual = fib(1)
expected = 1
self.assertEqual(actual, expected)
def test_second_fibonacci(self):
actual = fib(2)
expected = 1
self.assertEqual(actual, expected)
def test_third_fibonacci(self):
actual = fib(3)
expected = 2
self.assertEqual(actual, expected)
def test_fifth_fibonacci(self):
actual = fib(5)
expected = 5
self.assertEqual(actual, expected)
def test_tenth_fibonacci(self):
actual = fib(10)
expected = 55
self.assertEqual(actual, expected)
def test_negative_fibonacci(self):
with self.assertRaises(Exception):
fib(-1)
unittest.main(verbosity=2)