diff --git a/2015/day17.scala b/2015/day17.scala
new file mode 100644
index 0000000..c393ec5
--- /dev/null
+++ b/2015/day17.scala
@@ -0,0 +1,60 @@
+package `2015`.day17
+
+import prelude.*
+import scala.collection.mutable.Map
+
+trait Pretty[A]:
+  extension (x: A) inline def pretty: String
+
+inline given [A]: Pretty[IterableOnce[A]] with
+  extension (x: IterableOnce[A])
+    inline def pretty = x.iterator.mkString("[", ", ", "]")
+
+extension [A](x: Iterable[A])
+  def combinationsRepeating(size: Int): Iterator[Seq[A]] =
+    x.zipWithIndex.toSeq.combinations(size).map(_.map(_._1))
+
+trait Logger:
+  def log(msg: => Any): Unit
+
+given Logger = NoopLogger
+
+object NoopLogger extends Logger:
+  def log(msg: => Any): Unit = {}
+
+object PrintLogger extends Logger:
+  def log(msg: => Any): Unit = println(msg)
+
+def part1(target: Int, containers: Iterable[Int])(using logger: Logger) =
+  val dp = Map[Int, Int](0 -> 1)
+  logger.log(s"target: $target, containers: $containers, dp: ${dp.pretty}")
+
+  for currentSize <- containers do
+    for nextSize <- (target to currentSize by -1) do
+      for x <- dp.get(nextSize - currentSize) do
+        dp(nextSize) = dp.getOrElse(nextSize, 0) + x
+        logger.log(
+          f"ways to fit $nextSize%2dL => using $currentSize%2dL: x${dp(nextSize)} ($x%2d ways to fit leftover ${nextSize - currentSize}%2dL), dp: ${dp.pretty}",
+        )
+  dp(target)
+
+def part2(target: Int, containers: Seq[Int])(using logger: Logger) =
+  def matches(kinds: Int) =
+    containers
+      .combinationsRepeating(kinds)
+      .tapEach(logger.log(_))
+      .count(_.sum == target)
+      .tap(logger.log(_))
+
+  (1 to containers.size)
+    .map(matches)
+    .tapEach(logger.log(_))
+    .find(_ > 0)
+    .getOrElse(throw new Exception("no match found"))
+
+@main def main() =
+  val containers = fromFile(".cache/2015/17.txt").getLines.map(_.toInt).toSeq
+  val target = 150
+
+  println(part1(target, containers))
+  println(part2(target, containers))
diff --git a/2015/day17.test.scala b/2015/day17.test.scala
new file mode 100644
index 0000000..f008e0d
--- /dev/null
+++ b/2015/day17.test.scala
@@ -0,0 +1,16 @@
+package `2015`.day17
+
+import prelude.*
+import munit.FunSuite
+import `2015`.day17.*
+
+
+class Tests extends FunSuite:
+  // given Logger = PrintLogger
+  test("part 1"):
+    val res = part1(target = 25, containers = Seq(20, 15, 10, 5, 5))
+    assertEquals(res, 4)
+
+  test("part2"):
+    val res = part2(target = 25, containers = Seq(20, 15, 10, 5, 5))
+    assertEquals(res, 3)