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package testview;
trait Tree[+a <% Ordered[a]] {
def insert[b >: a <% Ordered[b]](x: b): Tree[b];
def elements: List[a]
}
object Empty extends Tree[All] {
def insert[b >: All <% Ordered[b]](x: b): Tree[b] = new Node(x, Empty, Empty);
def elements: List[All] = List();
}
class Node[a <% Ordered[a]](elem: a, l: Tree[a], r: Tree[a]) extends Tree[a] {
def insert[b >: a <% Ordered[b]](x: b): Tree[b] =
if (x == elem) this
else if (x < elem) new Node(elem, l insert x, r)
else new Node(elem, l, r insert x);
def elements: List[a] =
l.elements ::: List(elem) ::: r.elements
}
case class Str(elem: String) extends Ordered[Str] {
def compareTo[b >: Str <% Ordered[b]](that: b): int = that match {
case that1: Str => this.elem compareTo that1.elem
case _ => -(that compareTo this)
}
}
object Test {
// import O.view;
private def toCharList(s: String): List[Char] =
if (s.length() == 0) List()
else s.charAt(0) :: toCharList(s.substring(1));
def main(args: Array[String]) = {
{
var t: Tree[String] = Empty;
for (val s <- args) {
t = t insert s
}
System.out.println(t.elements)
}
{
var t: Tree[Str] = Empty;
for (val s <- args) {
t = t insert Str(s)
}
System.out.println(t.elements)
}
{
var t: Tree[List[char]] = Empty;
for (val s <- args) {
t = t insert toCharList(s)
}
System.out.println(t.elements)
}
}
}
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