50. Pow(x, n)
Содержание
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
