From 658b037f5966c170bca661d19ed034a2d06567bc Mon Sep 17 00:00:00 2001
From: Neil Smith <neil.git@njae.me.uk>
Date: Mon, 10 Dec 2018 14:33:46 +0000
Subject: [PATCH] Day 9 with pointed list

---
 advent-of-code.cabal               | 10 +++++
 src/advent09/advent09-pointlist.hs | 65 +++++-------------------------
 2 files changed, 21 insertions(+), 54 deletions(-)

diff --git a/advent-of-code.cabal b/advent-of-code.cabal
index 2ccee5c..83c71a9 100644
--- a/advent-of-code.cabal
+++ b/advent-of-code.cabal
@@ -110,3 +110,13 @@ executable advent09
                      , text
                      , megaparsec
                      , containers
+
+executable advent09pl
+  hs-source-dirs:      src/advent09
+  main-is:             advent09-pointlist.hs
+  default-language:    Haskell2010
+  build-depends:       base >= 4.7 && < 5
+                     , text
+                     , megaparsec
+                     , containers
+                     , pointedlist
diff --git a/src/advent09/advent09-pointlist.hs b/src/advent09/advent09-pointlist.hs
index 0cae08b..d551180 100644
--- a/src/advent09/advent09-pointlist.hs
+++ b/src/advent09/advent09-pointlist.hs
@@ -2,7 +2,7 @@
 
 import Data.List
 
-import Data.Foldable (toList)
+import Data.Maybe (fromJust)
 
 import Data.Text (Text)
 import qualified Data.Text.IO as TIO
@@ -17,38 +17,21 @@ import qualified Control.Applicative as CA
 -- import Data.Map.Strict ((!))
 import qualified Data.Map.Strict as M
 
-import qualified Data.Sequence as Q
-import Data.Sequence ((<|), (|>), ViewL((:<)), ViewR((:>)) )
+import Data.List.PointedList (PointedList)
+import qualified Data.List.PointedList.Circular as PL
 
--- zipper of left, current, right
-data Circle = Circle (Q.Seq Integer) Integer (Q.Seq Integer) deriving (Eq)
+type Circle = PointedList Integer
 type Score = M.Map Integer Integer -- player -> score
 data Game = Game Circle Score deriving (Show, Eq)
 
-instance Show Circle where
-    show (Circle left current right) = (showSide left) ++ " (" ++ (show current) ++ ") " ++ (showSide right)
-        where showSide s = intercalate " " $ map show $ toList s
-
 main :: IO ()
 main = do 
         text <- TIO.readFile "data/advent09.txt"
         let (numberOfPlayers, numberOfMarbles) = successfulParse text
-        -- let numberOfPlayers = 10
-        -- let numberOfMarbles = 1618
-        -- print $ take 5 $ scanl (\c n -> insertAfter n $ stepClockwise c) (createCircle 0) [1..]
-        -- print $ playGame numberOfPlayers numberOfMarbles
-        -- print (let p = 10 ; m = 1618 in part1 p m)
-        -- print (let p = 13 ; m = 7999 in part1 p m)
-        -- print (let p = 17 ; m = 1104 in part1 p m)
-        -- print (let p = 21 ; m = 6111 in part1 p m)
-        -- print (let p = 30 ; m = 5807 in part1 p m)
         print $ part1 numberOfPlayers numberOfMarbles
         print $ part1 numberOfPlayers (numberOfMarbles * 100)
 
-
-        -- putStrLn $ part1 schedule
-        -- print $ part2 schedule
-
+part1 :: Integer -> Integer -> Integer
 part1 players marbles = highScore $ playGame players marbles
 
 playGame :: Integer -> Integer -> Game
@@ -62,43 +45,17 @@ createGame :: Game
 createGame = Game (createCircle 0) M.empty
 
 createCircle :: Integer -> Circle
-createCircle current = Circle Q.empty current Q.empty
-
-currentMarble :: Circle -> Integer
-currentMarble (Circle _ m _) = m
-
-stepClockwise :: Circle -> Circle
-stepClockwise (Circle left current right)
-    | (Q.null left) && (Q.null right) = Circle left current right
-    | (Q.null right) = stepClockwise (Circle Q.empty current left)
-    | otherwise = Circle (left |> current) r rs
-    where (r :< rs) = Q.viewl right
-
-stepAntiClockwise :: Circle -> Circle
-stepAntiClockwise (Circle left current right)
-    | (Q.null left) && (Q.null right) = Circle left current right
-    | (Q.null left) = stepAntiClockwise (Circle right current Q.empty)
-    | otherwise = Circle ls l (current <| right)
-    where (ls :> l) = Q.viewr left
-
-insertAfter :: Integer -> Circle -> Circle
-insertAfter new (Circle left current right) = Circle (left |> current) new right
-
-removeCurrent :: Circle -> Circle
-removeCurrent (Circle left _ right) 
-    | Q.null right = Circle ls l Q.empty
-    | otherwise = Circle left r rs
-    where (l :< ls) = Q.viewl left
-          (r :< rs) = Q.viewl right
+createCircle current = PL.singleton current
+
 
 makeMove :: Game -> (Integer, Integer) -> Game
 makeMove (Game circle score) (player, marble) =
     if marble `mod` 23 == 0
-    then let circle' = (iterate stepAntiClockwise circle) !! 7
-             score' = updateScore score player (marble + (currentMarble circle'))
-             circle'' = removeCurrent circle'
+    then let circle' = (iterate PL.previous circle) !! 7
+             score' = updateScore score player (marble + (PL._focus circle'))
+             circle'' = fromJust $ PL.deleteRight circle'
          in Game circle'' score'
-    else let circle' = insertAfter marble (stepClockwise circle)
+    else let circle' = PL.insertRight marble (PL.next circle)
          in Game circle' score
 
 updateScore :: Score -> Integer -> Integer -> Score
-- 
2.34.1