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50. Pow(x, n)

Difficulty Topics

Description

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.
  • -104 <= xn <= 104

Solution

powx-n.py
class Solution:
    def myPow(self, x: float, n: int) -> float:
        if n == 0: return 1

        if n < 0:
            n = -n
            x = 1 / x

        return self.myPow(x * x, n // 2) if n % 2 == 0 else x * self.myPow(x * x, n // 2)