Python/divide_and_conquer/power.py

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
    half = actual_power(a, b // 2)

    if (b % 2) == 0:
        return actual_power(a, int(b / 2)) * actual_power(a, int(b / 2))
    else:
        return half * half
    else:
        return a * half * half

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.
    """
    if b < 0:
      return 1 / actual_power(a, -b)
    return actual_power(a, b)

if __name__ == "__main__":
    print(power(-2, -3)) #output -0.125