new(haskell): Solved day 1 second puzzle.

diff --git a/day1/Main.hs b/day1/Main.hs
index d571ad2..d3eac3d 100644 (file)
--- a/day1/Main.hs
+++ b/day1/Main.hs
@@ -1,10 +1,25 @@
-
 f1 :: [Int] -> Int
 f1 [] = 0
+-- y x(cur)
 f1 (k : ks) = foldr (\x g y -> let n = g x in if y < x then n + 1 else n) (const 0) ks k
 
+f2 :: [Int] -> Int
+f2 [] = 0
+f2 (k1 : k2 : ks) = fst $ foldr go (\_ _ -> (0, 0)) ks k1 k2
+ where
+  go ::
+    Int ->
+    (Int -> Int -> (Int, Int)) ->
+    (Int -> Int -> (Int, Int))
+  -- w y x(cur)
+  go x g w y =
+    let (n, next) = g y x
+        cur = w + y + x
+     in if next > cur then (n + 1, cur) else (n, cur)
+
 main :: IO ()
 main = do
-    c <- readFile "day1/input.txt"
-    let xs = map read (lines c)
-    print (f1 xs)
+  c <- readFile "day1/input.txt"
+  let xs = map read (lines c)
+  print $ "Answer1: " ++ show (f1 xs)
+  print $ "Answer2: " ++ show (f2 xs)