Day 11: a lot

day11long

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+Monkey 0:
+  Starting items: 52, 60, 85, 69, 75, 75
+  Operation: new = old * 17
+  Test: divisible by 13
+    If true: throw to monkey 6
+    If false: throw to monkey 7
+
+Monkey 1:
+  Starting items: 96, 82, 61, 99, 82, 84, 85
+  Operation: new = old + 8
+  Test: divisible by 7
+    If true: throw to monkey 0
+    If false: throw to monkey 7
+
+Monkey 2:
+  Starting items: 95, 79
+  Operation: new = old + 6
+  Test: divisible by 19
+    If true: throw to monkey 5
+    If false: throw to monkey 3
+
+Monkey 3:
+  Starting items: 88, 50, 82, 65, 77
+  Operation: new = old * 19
+  Test: divisible by 2
+    If true: throw to monkey 4
+    If false: throw to monkey 1
+
+Monkey 4:
+  Starting items: 66, 90, 59, 90, 87, 63, 53, 88
+  Operation: new = old + 7
+  Test: divisible by 5
+    If true: throw to monkey 1
+    If false: throw to monkey 0
+
+Monkey 5:
+  Starting items: 92, 75, 62
+  Operation: new = old * old
+  Test: divisible by 3
+    If true: throw to monkey 3
+    If false: throw to monkey 4
+
+Monkey 6:
+  Starting items: 94, 86, 76, 67
+  Operation: new = old + 1
+  Test: divisible by 11
+    If true: throw to monkey 5
+    If false: throw to monkey 2
+
+Monkey 7:
+  Starting items: 57
+  Operation: new = old + 2
+  Test: divisible by 17
+    If true: throw to monkey 6
+    If false: throw to monkey 2

day11short

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+Monkey 0:
+  Starting items: 79, 98
+  Operation: new = old * 19
+  Test: divisible by 23
+    If true: throw to monkey 2
+    If false: throw to monkey 3
+
+Monkey 1:
+  Starting items: 54, 65, 75, 74
+  Operation: new = old + 6
+  Test: divisible by 19
+    If true: throw to monkey 2
+    If false: throw to monkey 0
+
+Monkey 2:
+  Starting items: 79, 60, 97
+  Operation: new = old * old
+  Test: divisible by 13
+    If true: throw to monkey 1
+    If false: throw to monkey 3
+
+Monkey 3:
+  Starting items: 74
+  Operation: new = old + 3
+  Test: divisible by 17
+    If true: throw to monkey 0
+    If false: throw to monkey 1

day11ungolfed.hs

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+import Control.Monad.State.Strict
+import Data.List
+
+data Monkey = Monkey {items :: [Int], operation :: Int -> Int, test :: (Int, Int, Int), inspected :: Int}
+
+op :: String -> Int -> Int -> Int
+op "*" = (*)
+op "+" = (+)
+
+pread "old" old = old
+pread i _ = read i
+
+parseOp :: [String] -> Int -> Int
+parseOp [a,o,b] = \old -> op o (pread a old) (pread b old)
+
+parseDiv :: String -> Int
+parseDiv = read.last.words
+
+parse [_,i,o,d,t,f] = Monkey (read$"["++drop 18 i++"]")(parseOp $ words$drop 19 o) (parseDiv d, parseDiv t, parseDiv f) 0
+
+instance Show Monkey where
+  show (Monkey i o t ins) = "Monkey {items = " ++ show i ++ "} ("++ show ins ++")"
+
+instance Eq Monkey where
+ m1 == m2 = inspected m1 == inspected m2
+
+instance Ord Monkey where
+  m1<=m2 = inspected m1 <= inspected m2
+
+type MState = [Monkey]
+
+extract :: Int -> [a] -> ([a], a, [a])
+extract i m|(f,(c:b))<-splitAt i m=(f,c,b)
+
+addTo :: Int -> Int -> State MState ()
+addTo monkeyId item = do
+  monkeys <- get
+  let (f,monkey,b) = extract monkeyId monkeys
+  let newMonkey = monkey {items = items monkey ++ [item]}
+  put $ f ++ (newMonkey:b)
+
+
+step :: (Int -> Int) -> Int -> State MState ()
+step op monkeyId = do
+  monkeys <- get
+  let monkey = monkeys !! monkeyId
+  let newInspected = inspected monkey + length (items monkey)
+  forM_ (items monkey) $ \item -> do
+    let new = operation monkey item
+    let unworried = op new
+    let (divis, mtrue, mfalse) = test monkey
+    if unworried `mod` divis == 0
+      then addTo mtrue unworried 
+      else addTo mfalse unworried 
+  let newMonkey = monkey {items = [], inspected = newInspected}
+  m <- get
+  let (f,c,b) = extract monkeyId m
+  put (f ++ (newMonkey:b))
+
+monkeyRound :: (Int -> Int) -> State MState ()
+monkeyRound op = do
+  l <- length<$>get
+  forM_ [0..l-1] $ step op
+
+monkeyRounds i op = do
+  forM_ [1..i] $ \_-> monkeyRound op
+
+maxdivis = product.map((\(a,b,c)->a).test)
+
+compute monkeys n op = product $ map inspected$ take 2$reverse$sort$execState (monkeyRounds n op) monkeys
+
+main = do
+  monkeyFile <- map (parse.filter (/="")).groupBy(const (/="")).lines<$>readFile "day11long"
+  print $ compute monkeyFile 20 (`div` 3)
+  print $ compute monkeyFile 10000 (`mod` (maxdivis monkeyFile))