From 6b4d4466aee35bd748f252a3612054ce70a190e2 Mon Sep 17 00:00:00 2001
From: Xiretza <xiretza@xiretza.xyz>
Date: Wed, 2 Dec 2020 10:12:00 +0100
Subject: [PATCH] 2020 day1/haskell: add solution

---
 2020/day1/day1.hs | 12 ++++++++++++
 1 file changed, 12 insertions(+)
 create mode 100644 2020/day1/day1.hs

diff --git a/2020/day1/day1.hs b/2020/day1/day1.hs
new file mode 100644
index 0000000..643ff82
--- /dev/null
+++ b/2020/day1/day1.hs
@@ -0,0 +1,12 @@
+{-# LANGUAGE TypeApplications #-}
+
+import Data.List
+import Data.Maybe
+import Control.Monad
+
+find_n_summing :: (Num a, Eq a) => a -> Int -> [a] -> Maybe [a]
+find_n_summing to = (find ((to ==) . sum) .) . replicateM
+
+main = do
+    nums <- fmap read <$> lines <$> readFile "input.txt"
+    mapM_ print $ product <$> fromJust <$> flip (find_n_summing 2020) nums <$> [2, 3]