Power_x_n.py

"""
Implement pow(x, n), which calculates x raised to the power n (i.e., xn).

 

Example 1:

Input: x = 2.00000, n = 10
Output: 1024.00000
Example 2:

Input: x = 2.10000, n = 3
Output: 9.26100
Example 3:

Input: x = 2.00000, n = -2
Output: 0.25000
Explanation: 2-2 = 1/22 = 1/4 = 0.25
 

Constraints:

-100.0 < x < 100.0
-231 <= n <= 231-1
n is an integer.
Either x is not zero or n > 0.
-104 <= xn <= 104
"""
class Solution:
    def myPow(self, x: float, n: int) -> float:
        # Check for equal to zero 0
        if n == 0:
            return 1
        # Check for negative
        if n < 0:
            return self.myPow(1/x, -n)
        # Check for even numbers
        elif n % 2 == 0:
            temp = self.myPow(x, n/2)
            return temp*temp
        # Check for odd numbers
        else:
            return x * self.myPow(x, n-1)