Update LinearSearch.scala

There are a few ways to improve this:
Thanks for this resource!  Just a few suggestions for readability, performance and lack of stack overflows.
1. Use a Vector - you're doing random accesses which are O(N) for Lists but O(1) for Vectors.
2. Make conditionals positive, much easier to reason about than negative conditionals
3. (2) enables the recursive call to Iter() to be last in the Iter function, which allows Iter to be tail recursive, which means no matter how long the parameter is it will never cause a stack overflow.

Author: sjnester

src/main/scala/Search/LinearSearch.scala

@@ -10,16 +10,14 @@ object LinearSearch {
     * @param elem - a integer to search for in the @args
     * @return - index of the @elem or -1 if elem is not fount in the @arr
     */
-  def linearSearch(arr: List[Int], elem: Int): Int = {
-    def iter(index: Int): Int = {
-      if (index != arr.length) {
-        if (arr(index) != elem) iter(index + 1)
-        else index
-      } else
-        -1
+  def linearSearch(arr: Vector[Int], elem: Int): Int = {
+    def iter(index: Int): Int = 
+      if (index == arr.length) -1
+      else if (arr(index) == elem) index
+      else iter(index + 1)
     }
 
     iter(0)
   }
 
-}
+}