Implement pow(a, b) logN

Pow.java

public class Pow {
    
    public double myPow(double x, int n) {
        
        boolean isNegative = n < 0; 
        
        if(isNegative)
            n = n * -1;
        
        double result = innerPow(x, n);
        
        if(isNegative)
            return 1 / result;
        
        return result;
    }
    
    
    private double innerPow(double a, int b){
        
        if(a == 0) return 0;
        if(a == 1 || b == 0) return 1;
        if(b == 1) return a;

        double result = innerPow(a, b / 2);
        
        result = result * result;
        
        if((b & 1) === 1)
            result = result * a;
            
        return result;
    }
}