Bubble sort in scala implementation (algorithm-archivists#417)

* add scala to book.json

* add scala example for bubblesort

* fix misaligned brace

* simplfy bubble sort implemtation

* fix line numbers in md

* fix line numbers in md

* add name to contributors

Author: kenpower

CONTRIBUTORS.md

@@ -34,3 +34,4 @@ This file lists everyone, who contributed to this repo and wanted to show up her
 - Trashtalk
 - Cyrus Burt
 - Patrik Tesarik
+- Ken Power

book.json

@@ -140,6 +140,10 @@
           "lang": "f90",
           "name": "Fortran90"
         },
+        {
+          "lang": "scala",
+          "name": "Scala"
+        },
         {
           "lang": "emojic",
           "name": "Emojicode"

contents/bubble_sort/bubble_sort.md

@@ -52,6 +52,8 @@ This means that we need to go through the vector $$\mathcal{O}(n^2)$$ times with
 [import:5-9, lang:"nim"](code/nim/bubble_sort.nim)
 {% sample lang="f90" %}
 [import:19-40, lang:"fortran"](code/fortran/bubble.f90)
+{% sample lang="scala" %}
+[import:3-14, lang:"scala"](code/scala/bubble_sort.scala)
 {% sample lang="emojic" %}
 [import:2-14, lang:"emojicode"](code/emojicode/bubble_sort.emojic)
 {% endmethod %}
@@ -111,6 +113,8 @@ Trust me, there are plenty of more complicated algorithms that do precisely the
 [import, lang:"nim"](code/nim/bubble_sort.nim)
 {% sample lang="f90" %}
 [import, lang:"fortran"](code/fortran/bubble.f90)
+{% sample lang="scala" %}
+[import, lang:"scala"](code/scala/bubble_sort.scala)
 {% sample lang="emojic" %}
 [import, lang:"emojicode"](code/emojicode/bubble_sort.emojic)
 {% endmethod %}

contents/bubble_sort/code/scala/bubble_sort.scala

@@ -0,0 +1,22 @@
+object BubbleSort {
+
+  def bubbleDown(list: List[Int]): List[Int] =
+    list match {
+      case a :: b :: tail if a < b => b :: bubbleDown(a :: tail)
+      case a :: b :: tail => a :: bubbleDown(b :: tail)
+      case _ => list
+    }
+
+  def bubbleSort(list: List[Int]): List[Int] =
+    bubbleDown(list) match {
+      case unsorted :+ smallest => smallest :: bubbleDown(unsorted)
+      case _ => list
+    }
+
+  def main(args: Array[String]): Unit = {
+    val unsorted = List(9, 2, 0, 5, 3, 8, 1, 9, 4, 0, 7, 0, 9, 9, 0)
+
+    println("Unsorted list is " + unsorted)
+    println("  Sorted list is " + bubbleSort(unsorted))
+  }
+}