subtree(users/wpcarro): docking briefcase at '24f5a642' r/3226

git-subtree-dir: users/wpcarro
git-subtree-mainline: 464bbcb15c09813172c79820bcf526bb10cf4208
git-subtree-split: 24f5a642af3aa1627bbff977f0a101907a02c69f
Change-Id: I6105b3762b79126b3488359c95978cadb3efa789

1 files changed, 33 insertions, 0 deletions

diff --git a/users/wpcarro/assessments/semiprimes/server/lib/server.ex b/users/wpcarro/assessments/semiprimes/server/lib/server.ex
new file mode 100644
index 000000000000..7ab5e905b5a0
--- /dev/null
+++ b/users/wpcarro/assessments/semiprimes/server/lib/server.ex
@@ -0,0 +1,33 @@
+defmodule Server do
+  @moduledoc """
+  Documentation for `Server`.
+  """
+
+  @doc """
+  If `n` contains exactly two prime factors, return those prime factors;
+  otherwise, return nothing.
+  """
+  def semiprime(n) do
+    case Cache.get(n) do
+      nil ->
+        case do_semiprime(n) do
+          nil ->
+            nil
+
+          res ->
+            Cache.put(n, res)
+            {:miss, res}
+        end
+
+      hit ->
+        {:hit, hit}
+    end
+  end
+
+  defp do_semiprime(n) do
+    case Math.factor(n) do
+      [_, _] = res -> res
+      _ -> nil
+    end
+  end
+end