added ClosestNumbers exercise

Author: andersonkmi

src/main/scala/org/codecraftlabs/leetcode/ClosestNumbers.scala

@@ -0,0 +1,9 @@
+package org.codecraftlabs.leetcode
+
+object ClosestNumbers {
+  def closestNumbers(arr: Array[Int]): Array[Int] = {
+    val sortedArray = arr.sorted.toList
+    val smallestDiff = sortedArray.sliding(2).map { case Seq(x, y, _*) => (y - x) }.toList.min
+    sortedArray.sliding(2).toList.filter(pair => pair.last - pair.head == smallestDiff).flatten.toArray
+  }
+}