问这种方法的时间复杂度和辅助空间是多少？

EN

public Set<T> findRepeatedValues(List<T> list){
    Set<T> set = new HashSet<>();
    Set<T> repeatedValues = new HashSet<>();
    for (T i: list) {
        if (!set.add(i)) {
            repeatedValues.add(i);
        }
    }
    return repeatedValues;
}

@Test
public void findRepeatedStrings(){
    List<String> stringList = new ArrayList<String>(Arrays.asList("ali","mahdi","hadi","mahdi","mojtaba","mohammad","mojtaba"));
    RepeatedValues repeatedValues = new RepeatedValues();
    Set values = repeatedValues.findRepeatedValues(stringList);
    for (Object i :
            values) {
        System.out.println(i);
    }
}