PowXn.java

/* Implement pow(x, n), which calculates x raised to the power n (i.e., xn).

 ----Divide and Conqueror APPROACH----

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.
-104 <= xn <= 104
*/

class Solution {
    public double myPow(double x, int n) {
     double temp;
        if( n == 0)
            return 1;
        temp = myPow(x, n/2); 
          
        if (n%2 == 0)
            return temp*temp;
        else
        {
            if(n > 0)
                return x * temp * temp;
            else
                return (temp * temp) / x;
        }
        
    }
}
class PowXn {
    public static void main(String[] args) {
       double x=2.00;
       int y=10;
       Solution s=new Solution();
       System.out.println(s.myPow(x,y));
    }
}