1 files changed, 11 insertions, 0 deletions
diff --git a/H57.hs b/H57.hs
new file mode 100644
index 0000000..0af879f
--- /dev/null
+++ b/H57.hs
@@ -0,0 +1,11 @@
+import Tree
+
+construct :: Ord a => [a] -> Tree a
+construct = foldl add Empty
+
+add :: Ord a => Tree a -> a -> Tree a
+add Empty x = Branch x Empty Empty
+add t@(Branch a t1 t2) x = case compare x a of 
+    LT -> Branch a (add t1 x) t2
+    GT -> Branch a t1 (add t2 x)
+    EQ -> t