In Java, I was not able to pass the "Numerous Horses" validation by using a SortedSet (all other tests were green). Instead, I used an ArrayList as suggested by someone.
However, I performed some test on my side and if I add more than 50 numbers, the SortedSet is faster than the ArrayList. With less than 50 numbers, the time are equivalent.
Does someone have an idea why a List is better for this test than the Set?