From c681d5a28ead377ea2b82adaaf18f1c6e224f2e0 Mon Sep 17 00:00:00 2001
From: Chance Nelson <chance-nelson@nau.edu>
Date: Tue, 1 Oct 2019 23:58:15 -0700
Subject: [PATCH 1/3] add example functions for fibonacci sequence and
 memoization

---
 allalgorithms/numeric/fibonacci.py | 44 ++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 allalgorithms/numeric/fibonacci.py

diff --git a/allalgorithms/numeric/fibonacci.py b/allalgorithms/numeric/fibonacci.py
new file mode 100644
index 0000000..e875413
--- /dev/null
+++ b/allalgorithms/numeric/fibonacci.py
@@ -0,0 +1,44 @@
+# -*- coding: UTF-8 -*-
+#
+# Numeric Algorithms: Factorials and Memoization
+# The All ▲lgorithms library for python
+#
+# Contributed by: Chance
+# Github: @chance-nelson
+#
+
+
+def fibonacci(n):
+    """Compute the Fibonacci sequence number at a certain index
+
+    This is the obvious recursive approach, and runs on the order of O(n*2).
+    """
+    # Base case 1: fibonacci(1) == 0
+    if n == 1:
+        return 0
+
+    # Base case 2: fibonacci(2) == 1
+    elif n == 2:
+        return 1
+
+    return fibonacci(n-1) + fibonacci(n-2)
+
+
+def memoize(f):
+    """Special decorator to add memoization to any recursive function
+
+    Keep a cache of results from past runs. This cache can then be referenced
+    instead of calling the function again.
+    """
+    memory = {}
+    
+    def inner(num):
+        if num not in memory:
+            memory[num] = f(num)
+
+        return memory[num]
+
+    return inner
+
+
+fibonacci_memo = memoize(fibonacci)

From 64cf5f66ca00dfa13ef4f13d2dece2a6c95b1391 Mon Sep 17 00:00:00 2001
From: Chance Nelson <chance-nelson@nau.edu>
Date: Tue, 1 Oct 2019 23:58:42 -0700
Subject: [PATCH 2/3] add tests for fibonacci functions

---
 tests/test_numeric.py | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/tests/test_numeric.py b/tests/test_numeric.py
index 2be532d..a0c9a3f 100644
--- a/tests/test_numeric.py
+++ b/tests/test_numeric.py
@@ -1,6 +1,7 @@
 import unittest
 
 from allalgorithms.numeric import find_max
+from allalgorithms.fibonacci import fibonacci, fibonacci_memo
 
 
 class TestMax(unittest.TestCase):
@@ -9,5 +10,15 @@ def test_find_max_value(self):
         test_list = [3, 1, 8, 7, 4]
         self.assertEqual(8, find_max(test_list))
 
+
+class TestFibonacci(unittest.TestCase):
+
+    def test_recursive_fibonacci(self):
+        self.assertEqual(8, fibonacci(7))
+
+    def test_memoize_fibonacci(self):
+        self.assertEqual(8, fibonacci(7))
+
+
 if __name__ == "__main__":
     unittest.main()

From 47993f0aa122eee438cf14861d3738b407cd7454 Mon Sep 17 00:00:00 2001
From: Chance Nelson <chance-nelson@nau.edu>
Date: Tue, 1 Oct 2019 23:59:01 -0700
Subject: [PATCH 3/3] add fibonacci import

---
 allalgorithms/numeric/__init__.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/allalgorithms/numeric/__init__.py b/allalgorithms/numeric/__init__.py
index cd1f5cc..5dfa7ad 100644
--- a/allalgorithms/numeric/__init__.py
+++ b/allalgorithms/numeric/__init__.py
@@ -1 +1,2 @@
-from .max_numbers import find_max
\ No newline at end of file
+from .max_numbers import find_max
+from .fibonacci import fibonacci, fibonacci_memo