diff --git a/recursion/__init__.py b/recursion/__init__.py
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/recursion/factorial.py b/recursion/factorial.py
new file mode 100644
index 000000000000..0fe09e2005bf
--- /dev/null
+++ b/recursion/factorial.py
@@ -0,0 +1,30 @@
+"""
+Fibonacci
+https://en.wikipedia.org/wiki/Fibonacci_number
+"""
+
+
+def factorial(number: int) -> int:
+ """
+ Compute the factorial of a non-negative integer using recursion.
+
+ >>> factorial(5)
+ 120
+ >>> factorial(0)
+ 1
+ >>> factorial(1)
+ 1
+ >>> factorial(3)
+ 6
+ >>> factorial(10)
+ 3628800
+ >>> factorial(-1)
+ Traceback (most recent call last):
+ ...
+ ValueError: Input must be a non-negative integer.
+ """
+ if number < 0:
+ raise ValueError("Input must be a non-negative integer.")
+ if number == 0:
+ return 1
+ return number * factorial(number - 1)
diff --git a/recursion/tests/__init__.py b/recursion/tests/__init__.py
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/recursion/tests/test_factorial.py b/recursion/tests/test_factorial.py
new file mode 100644
index 000000000000..91bcc2bb2c61
--- /dev/null
+++ b/recursion/tests/test_factorial.py
@@ -0,0 +1,15 @@
+import pytest
+
+from recursion.factorial import factorial
+
+
+def test_factorial_valid_inputs() -> None:
+ assert factorial(0) == 1
+ assert factorial(1) == 1
+ assert factorial(5) == 120
+ assert factorial(10) == 3628800
+
+
+def test_factorial_invalid_input() -> None:
+ with pytest.raises(ValueError):
+ factorial(-1)
pFad - Phonifier reborn
Pfad - The Proxy pFad of © 2024 Garber Painting. All rights reserved.
Note: This service is not intended for secure transactions such as banking, social media, email, or purchasing. Use at your own risk. We assume no liability whatsoever for broken pages.
Alternative Proxies:
Alternative Proxy
pFad Proxy
pFad v3 Proxy
pFad v4 Proxy