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authorWilliam Carroll <wpcarro@gmail.com>2020-01-15T14·25+0000
committerWilliam Carroll <wpcarro@gmail.com>2020-01-15T14·25+0000
commitd4d8397e5ffe6734ed5861e48ce475848956a3fe (patch)
tree7f0f8563750a2084ad9a4b9908cbb5316fe6bf10 /data_structures_and_algorithms/nth-fibonacci.py
parentb4ee283b23b8a85c75339e07b0adf43d1c3ca770 (diff)
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.
Diffstat (limited to 'data_structures_and_algorithms/nth-fibonacci.py')
-rw-r--r--data_structures_and_algorithms/nth-fibonacci.py59
1 files changed, 59 insertions, 0 deletions
diff --git a/data_structures_and_algorithms/nth-fibonacci.py b/data_structures_and_algorithms/nth-fibonacci.py
new file mode 100644
index 000000000000..cdb2846ea338
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+++ b/data_structures_and_algorithms/nth-fibonacci.py
@@ -0,0 +1,59 @@
+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)