added final exam preparation

src/FinalPrep1/Ex1.sc

@@ -0,0 +1,26 @@
+def insertion[T](x: T, xs: List[T]): List[List[T]] = {
+  return (0 to xs.length).map((i: Int) => {
+    val p = xs.splitAt(i)
+    p._1 ::: (x :: p._2)
+  }).toList
+
+  def buildInsertions(x: T, xs: List[T], before: List[T]): List[List[T]] = {
+    xs match {
+      case Nil => (before :+ x) :: Nil
+      case head::tail => (before ::: (x :: xs)) :: buildInsertions(x, tail, before :+ head)
+    }
+  }
+  buildInsertions(x, xs, Nil)
+}
+
+insertion(1, List(2,3,4))
+
+def permutation[T](xs: List[T]): List[List[T]] = {
+  xs match {
+    case head::tail => permutation(tail) flatMap (perm => insertion(head, perm))
+    case _ => List(xs)
+  }
+}
+
+
+permutation(List(1,2,3))