[LeetCode] Pow(x,n)

Thought:
Divide and Conquer.

Code:
public class Solution {
    public double pow(double x, int n) {
        boolean isNeg = false;
        if (n < 0) {
            n = - n;
            isNeg = true;
        }
        return isNeg ? 1 / helper(x, n): helper(x, n);       
    }
    public double helper(double x, int n) {      
       
        if (n == 0) return 1;       
        double result = pow(x, n / 2);
       
        if (n % 2 == 0) return result * result;
        return result * result * x;
    }
   
}