Hello, I'm trying to determine the algorithmic complexity of the function below, which determines if a string has been rotated (for example, a string "abcd" has been rotated to "bcda"). I believe the following runs in O(n), but I just wanted to verify.

public class Rotate{

public static void main(String[] args) { String first = "abcd"; String second = "cdba";

System.out.println(isRotated(first, second); } private static boolean isRotated(String first, String second){ if(first == null or second == null) {

return false;

} if (first.length == second.length && (first + second).indexOf(str2) > 0) {

return true;

}

return false; } }