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.- Either
x
is not zero orn > 0
. -104 <= xn <= 104
Solution
Python3
class Solution:
def myPow(self, x: float, n: int) -> float:
if n < 0:
n = -n
x = 1 / x
def p(base, k):
if k == 0: return 1
res = p(base, k // 2)
if k % 2 == 0:
return res * res
else:
return res * res * base
return p(x, n)