ummels · November 26, 2014 17:05 · Nov 26, 2014
diff --git a/mergestream.scala b/mergestream.scala
@@ -0,0 +1,22 @@
+object Util {
+  /** Merges a collection of streams into a single stream.
+    *
+    * Returns a sorted stream if all input streams are sorted.
+    */
+  def mergeStreams[A](streams: Traversable[Stream[A]])(implicit ord: Ordering[A]): Stream[A] = {
+    val streams1 = streams.toList filterNot (_.isEmpty) sortBy (_.head)
+    if (streams1.isEmpty)
+      Stream.empty
+    else {
+      val first = streams1.head
+      first.head #:: mergeStreams(first.tail :: streams1.tail)
+    }
+  }
+
+  /** Merges several streams into a single stream.
+    *
+    * Returns a sorted stream if all input streams are sorted.
+    */
+  def mergeStreams[A](streams: Stream[A]*)(implicit ord: Ordering[A]): Stream[A] =
+    mergeStreams(streams)
+}