Data commit

Task/Longest-increasing-subsequence/Scala/longest-increasing-subsequence-1.scala

@@ -0,0 +1,33 @@
+object LongestIncreasingSubsequence extends App {
+  val tests = Map(
+    "3,2,6,4,5,1" -> Seq("2,4,5", "3,4,5"),
+    "0,8,4,12,2,10,6,14,1,9,5,13,3,11,7,15" -> Seq("0,2,6,9,11,15", "0,2,6,9,13,15", "0,4,6,9,13,15", "0,4,6,9,11,15")
+  )
+
+  def lis(l: Array[Int]): Seq[Array[Int]] =
+    if (l.length < 2) Seq(l)
+    else {
+      def increasing(done: Array[Int], remaining: Array[Int]): Seq[Array[Int]] =
+        if (remaining.isEmpty) Seq(done)
+        else
+          (if (remaining.head > done.last)
+            increasing(done :+ remaining.head, remaining.tail)
+          else Nil) ++ increasing(done, remaining.tail) // all increasing combinations
+
+      val all = (1 to l.length)
+        .flatMap(i => increasing(l take i takeRight 1, l.drop(i + 1)))
+        .sortBy(-_.length)
+      all.takeWhile(_.length == all.head.length) // longest of all increasing combinations
+    }
+
+  def asInts(s: String): Array[Int] = s split "," map (_.toInt)
+
+  assert(tests forall {
+    case (given, expect) =>
+      val allLongests: Seq[Array[Int]] = lis(asInts(given))
+      println(
+        s"$given has ${allLongests.length} longest increasing subsequences, e.g. ${
+          allLongests.last.mkString(",")}")
+      allLongests.forall(lis => expect.contains(lis.mkString(",")))
+  })
+}

Task/Longest-increasing-subsequence/Scala/longest-increasing-subsequence-2.scala

@@ -0,0 +1,6 @@
+def powerset[A](s: List[A]) = (0 to s.size).map(s.combinations(_)).reduce(_++_)
+def isSorted(l:List[Int])(f: (Int, Int) => Boolean) = l.view.zip(l.tail).forall(x => f(x._1,x._2))
+def sequence(set: List[Int])(f: (Int, Int) => Boolean) = powerset(set).filter(_.nonEmpty).filter(x => isSorted(x)(f)).toList.maxBy(_.length)
+
+sequence(set)(_<_)
+sequence(set)(_>_)