Adding Scala example for Chapter 2 (#31)

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* Update 01_countdown.scala

* Update 02_greet.scala

* Update 02_greet.scala

* Create scala

* Delete scala

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* Update 01_selection_sort.scala

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01_introduction_to_algorithms/scala/01_introduction_to_algorithms.scala

@@ -0,0 +1,18 @@
+def binarySearch(list: List[Int], item: Int): Int = {
+  if(list.isEmpty) { println("Item not found"); return 0 }
+  val guessIndex = (list.length) / 2 
+  val guess = list(guessIndex)
+  if(item == guess) guess
+  else if(item < guess){
+    val halfList = list.take(list.length / 2)
+    binarySearch(halfList, item)
+  }
+  else {
+    val halfList = list.drop(1 + (list.length / 2))
+    binarySearch(halfList, item)
+  }
+}
+
+val myList = List(1,3,5,7,9)
+println(binarySearch(myList, 3))
+println(binarySearch(myList, -1))

02_selection_sort/scala/01_selection_sort.scala

@@ -0,0 +1,25 @@
+//Finds the smallest value in an array
+def findSmallest(arr: Array[Int]): Int = {
+  //Stores the smallest value
+  var smallest = arr(0)
+  for(i <- 1 until arr.length){
+    if(arr(i) < smallest) {
+      smallest = arr(i)
+    }
+  }
+  return smallest
+}
+
+//Sort array
+def selectionSort(arr: Array[Int]): Array[Int] = {
+  val newArr = new Array[Int](arr.length)
+  for(i <- 0 until arr.length){
+    //Finds the smallest element in the array and adds it to the new array
+    val smallest = findSmallest(arr)
+    newArr(i) = smallest
+    //Sets current smallest value in array above largest value to avoid reusing values
+    arr(arr.indexOf(smallest)) = arr.max + 1
+  }
+  return newArr
+}
+selectionSort(Array(5, 3, 6, 2, 10))