Initial data commit

Task/Sorting-algorithms-Patience-sort/Scala/sorting-algorithms-patience-sort.scala

@@ -0,0 +1,37 @@
+import scala.collection.mutable
+
+object PatienceSort extends App {
+  def sort[A](source: Iterable[A])(implicit bound: A => Ordered[A]): Iterable[A] = {
+    val  piles = mutable.ListBuffer[mutable.Stack[A]]()
+
+    def PileOrdering: Ordering[mutable.Stack[A]] =
+      (a: mutable.Stack[A], b: mutable.Stack[A]) => b.head.compare(a.head)
+
+    // Use a priority queue, to simplify extracting minimum elements.
+    val pq = new mutable.PriorityQueue[mutable.Stack[A]]()(PileOrdering)
+
+    // Create ordered piles of elements
+    for (elem <- source) {
+      // Find leftmost "possible" pile
+      // If there isn't a pile available, add a new one.
+      piles.find(p => p.head >= elem) match {
+        case Some(p) => p.push(elem)
+        case _ => piles += mutable.Stack(elem)
+      }
+    }
+
+    pq ++= piles
+
+    // Return a new list, by taking the smallest stack head
+    // until all stacks are empty.
+    for (_ <- source) yield {
+      val smallestList = pq.dequeue
+      val smallestVal = smallestList.pop
+
+      if (smallestList.nonEmpty) pq.enqueue(smallestList)
+      smallestVal
+    }
+  }
+
+  println(sort(List(4, 65, 2, -31, 0, 99, 83, 782, 1)))
+}