Python/divide_and_conquer/power.py
Pedram_Mohajer 70bd06db46
add doctest/document to actual_power and document to power ()
* Update power.py

* Update divide_and_conquer/power.py

---------

Co-authored-by: Tianyi Zheng <tianyizheng02@gmail.com>
2024-06-01 02:09:03 -07:00

52 lines
1.1 KiB
Python

def actual_power(a: int, b: int):
"""
Function using divide and conquer to calculate a^b.
It only works for integer a,b.
:param a: The base of the power operation, an integer.
:param b: The exponent of the power operation, a non-negative integer.
:return: The result of a^b.
Examples:
>>> actual_power(3, 2)
9
>>> actual_power(5, 3)
125
>>> actual_power(2, 5)
32
>>> actual_power(7, 0)
1
"""
if b == 0:
return 1
if (b % 2) == 0:
return actual_power(a, int(b / 2)) * actual_power(a, int(b / 2))
else:
return a * actual_power(a, int(b / 2)) * actual_power(a, int(b / 2))
def power(a: int, b: int) -> float:
"""
:param a: The base (integer).
:param b: The exponent (integer).
:return: The result of a^b, as a float for negative exponents.
>>> power(4,6)
4096
>>> power(2,3)
8
>>> power(-2,3)
-8
>>> power(2,-3)
0.125
>>> power(-2,-3)
-0.125
"""
if b < 0:
return 1 / actual_power(a, b)
return actual_power(a, b)
if __name__ == "__main__":
print(power(-2, -3))