Problem 19

src/main/scala/ninetyNineScalaProblems/Problem19.scala

@@ -0,0 +1,11 @@
+package ninetyNineScalaProblems
+
+
+object Problem19:
+    def rotateLeft(n: Int, list: List[Any]): List[Any] =
+        list match
+            case Nil =>
+                list
+            case _ =>
+                val splitIndex = (list.length + n) % list.length
+                Problem18.slice(splitIndex, list.length, list) ::: Problem18.slice(0, splitIndex, list)

src/test/scala/ninetyNineScalaProblems/Problem19Suite.scala

@@ -0,0 +1,17 @@
+package ninetyNineScalaProblems
+
+import scala.compiletime.ops.boolean
+
+class Problem19Suite extends munit.FunSuite:
+    List(
+        ((0, List(1, 2, 3, 4)), List(1, 2, 3, 4)),
+        ((1, List(1, 2, 3, 4)), List(2, 3, 4, 1)),
+        ((1, List(1)), List(1)),
+        ((0, List(1)), List(1)),
+        ((1, List()), List()),
+        ((0, List()), List()),
+        ((-1, List(1, 2, 3, 4)), List(4, 1, 2, 3)),
+    ).foreach:
+        case ((n, list), expected) =>
+            test(s"rotateLeft returns [$expected]"):
+                assertEquals(Problem19.rotateLeft(n, list), expected)