ふつう scala> SortedMap(2 -> "a", 1 -> "b", 3 -> "c") scala.collection.SortedMap[Int,java.lang.String] = Map(1 -> b, 2 -> a, 3 -> c) java.util.Comparator的な scala> val m = SortedMap.empty[Int, String](new Ordering[Int] { | def compare(a :…