Check if one integer is an integer power of another

Question

This is an interview question: \"Given 2 integers x and y, check if x is an integer power of y\" (e.g. for x = 8 and y = 2 the answer is \"true\", and for x = 10 and y = 2 \

Answer 1

It means log_y(x) should be an integer. Don't need any loop. in O(1) time

public class PowerTest {

    public static boolean isPower(int x, int y) {
        double d = Math.log(Math.abs(x)) / Math.log(Math.abs(y));

        if ((x > 0 && y > 0) || (x < 0 && y < 0)) {
            if (d == (int) d) {
                return true;
            } else {
                return false;
            }
        } else if (x > 0 && y < 0) {
            if ((int) d % 2 == 0) {
                return true;
            } else {
                return false;
            }
        } else {
            return false;
        }
    }

    /**
     * @param args
     */
    public static void main(String[] args) {

        System.out.println(isPower(-32, -2));
        System.out.println(isPower(2, 8));
        System.out.println(isPower(8, 12));
        System.out.println(isPower(9, 9));
        System.out.println(isPower(-16, 2));
        System.out.println(isPower(-8, -2));
        System.out.println(isPower(16, -2));
        System.out.println(isPower(8, -2));
    }

}