feat: Concatenate both factorial implementations (TheAlgorithms#8099)

* feat: Concatenate both factorial implementations

* fix: Rename factorial recursive method

maths/factorial_iterative.py → maths/factorial.py

@@ -34,6 +34,30 @@ def factorial(number: int) -> int:
     return value
 
 
+def factorial_recursive(n: int) -> int:
+    """
+    Calculate the factorial of a positive integer
+    https://en.wikipedia.org/wiki/Factorial
+
+    >>> import math
+    >>> all(factorial(i) == math.factorial(i) for i in range(20))
+    True
+    >>> factorial(0.1)
+    Traceback (most recent call last):
+        ...
+    ValueError: factorial() only accepts integral values
+    >>> factorial(-1)
+    Traceback (most recent call last):
+        ...
+    ValueError: factorial() not defined for negative values
+    """
+    if not isinstance(n, int):
+        raise ValueError("factorial() only accepts integral values")
+    if n < 0:
+        raise ValueError("factorial() not defined for negative values")
+    return 1 if n == 0 or n == 1 else n * factorial(n - 1)
+
+
 if __name__ == "__main__":
     import doctest