public boolean checkPowerOf2(int n) {
 return n > 0 && ((n & (n - 1)) == 0);
}



public boolean checkPowerOf2(int n) {
        // write your code here
        if (n == 1) return true;
        while (n > 0) {
            int m = n % 2;
            if (m == 0) {
                n = n / 2;
                if (n == 1)
                return true;
            }
            else {
                 return false;
            }
        }
        return false;
    }