50. Pow(x, n)

Implement pow(x, n).

Solution:

class Solution(object):
    def myPow(self, x, n):
        """
        :type x: float
        :type n: int
        :rtype: float
        """
        if n < 0:
            if x == 0:
                raise ZeroDivisionError('0.0 cannot be raised to a negative power')
            return 1 / self.myPow(x, -n)
        if n == 0:
            return 1
        val = self.myPow(x, n / 2)
        if n % 2 == 1:
            return x * val * val
        return val * val