50. Pow(x, n)

Обновлено: 2024-03-12
1 мин

Содержание

LeetCode problem

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

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

Approach 1:

class Solution:
    def myPow(self, x: float, n: int) -> float:
        return x ** n

Approach 2:

Recursive

class Solution:
    def myPow(self, x, n):
        if not n:
            return 1
        if n < 0:
            return 1 / self.myPow(x, -n)
        if n % 2:
            return x * self.myPow(x, n-1)
        return self.myPow(x * x, n/2)

Approach 3:

class Solution:
    def myPow(self, x, n):
        if n < 0:
            x = 1 / x
            n = -n
        pow = 1
        while n:
            if n & 1:
                pow *= x
            x *= x
            n >>= 1
        return pow