Pow(x, n) Java solution

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
-104 <= xn <= 104

Solution:

class Solution {

public double myPow(double x, int n) {

if(n>=0)

return positive(x,n);

else

return negative(x,n);

}

private double negative(double x, int n)

{

if(n==-1)

return 1/x;

double ans=myPow(x,n/2);

if(n%2==0)

return ans*ans;

else

return (1/x)*ans*ans;

}

private double positive(double x, int n)

{

if(n==0)

return 1;

double ans=myPow(x,n/2);

if(n%2==0)

return ans*ans;

else

return x*ans*ans;

}

Time Complexity: O(log n)

Also Read: Valid Perfect Square Java Solution

Pow(x, n) Java solution