Power of 2 - recursive and bitwise :)

gistfile1.txt

    public static Boolean powerCheck(int a) {
        return a!=0 && (a & a-1) == 0;
    }


    public static Boolean recursivePowerCheck(int a){
        if (a == 1) return true;
        if (a == 0 || a % 2 != 0) return false;
        return recursivePowerCheck(a/2);
    }