50 Powx N

Pow(x, n)

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 __init__(self):
        self.dt = {}

    def myPow(self, x: float, n: int) -> float:
        multiplier = 1
        if n < 0:
            return 1/self.calc(x, -n) 
        return self.calc(x, n) 
        


    def calc(self, x: float, n : int) -> int:
        if (str(x) + "$" + str(n)) in self.dt:
            return self.dt[str(x) + "$" + str(n)]

        
        if n <= 0:
            return 1
        if n == 1:
            return x
        result = 0
        if n % 2 == 0:
            result = self.calc(x, n/2) * self.calc(x, n/2)
        else:
            result = self.calc(x, (n+1)/2) * self.calc(x, (n-1)/2)
        self.dt[str(x) + "$" + str(n)] = result
        return result