Day 4

day04/Part1.hs

@@ -0,0 +1,18 @@
+module Part1 where
+
+import Commons
+
+
+getNWinningNumbers :: [Int] -> [Int] -> Int
+getNWinningNumbers _ [] = 0
+getNWinningNumbers winningNumbers (n: t) | n `elem` winningNumbers = 1 + getNWinningNumbers winningNumbers t
+                                         | otherwise = getNWinningNumbers winningNumbers t
+
+getPoints :: Card -> Int
+getPoints card = let nWinningNumbers = getNWinningNumbers (winningNumbers card) (numbers card)
+                 in if nWinningNumbers == 0
+                       then 0
+                       else 2 ^ (nWinningNumbers - 1)
+
+getAllPoints :: [Card] -> [Int]
+getAllPoints = map getPoints