050 pow(x, n)
50. Pow(x, n)
题目: https://leetcode.com/problems/powx-n/
难度:
Medium
Recursive
class Solution(object):
def myPow(self, x, n):
"""
:type x: float
:type n: int
:rtype: float
"""
if n == 0:
return 1
if n < 0:
return 1 / self.myPow(x, -n)
if n % 2 == 0:
return self.myPow(x*x, n/2)
else:
return x * self.myPow(x*x, n/2)
iterative
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
