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

Can’t Use Python Built-In Function

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
• -104 <= xn <= 104

Occurrences

class Solution:
 def myPow(self, x: float, n: int) -> float:
 
 if n==0: return 1
 
 def rec(power):
 if power==1: return x
 if power%2==0: #even power
 part=rec(power/2)
 return part*part
 else: #odd power
 part=rec(power//2)
 return x*part*part
 
 ans=rec(abs(n))
 return ans if n>0 else 1/ans

Complexity Analysis

• Time complexity : O(n)O(n). We will multiply x for n times.
• Space complexity: O(1)O(1). We only need one variable to store the final product of x.