From: Neil Smith <neil.git@njae.me.uk>
Date: Tue, 22 Dec 2020 09:30:13 +0000 (+0000)
Subject: Done day 13
X-Git-Url: https://git.njae.me.uk/?a=commitdiff_plain;h=7f33f392172a57f78d4de4a94af76a2f08428b66;p=advent-of-code-20.git

Done day 13
---

diff --git a/advent12/package.yaml b/advent12/package.yaml
index 5dbbf31..39a7c8b 100644
--- a/advent12/package.yaml
+++ b/advent12/package.yaml
@@ -58,6 +58,4 @@ executables:
     - base >= 2 && < 6
     - text
     - attoparsec
-    - containers
-    - vector
     
\ No newline at end of file
diff --git a/advent12/src/advent12.hs b/advent12/src/advent12.hs
index fb75491..c109c18 100644
--- a/advent12/src/advent12.hs
+++ b/advent12/src/advent12.hs
@@ -46,15 +46,15 @@ part2 actions = manhattan (positionW ship1) start
         ship0 = ShipW {positionW = start, waypoint = (10, 1)}
         ship1 = foldl actW ship0 actions
 
-apAc actions = ship1
-  where start = (0, 0)
-        ship0 = Ship {position = start, direction = East }
-        ship1 = foldl act ship0 actions
+-- apAc actions = ship1
+--   where start = (0, 0)
+--         ship0 = Ship {position = start, direction = East }
+--         ship1 = foldl act ship0 actions
 
-apAcW actions = ship1
-  where start = (0, 0)
-        ship0 = ShipW {positionW = start, waypoint = (10, 1) }
-        ship1 = foldl actW ship0 actions
+-- apAcW actions = ship1
+--   where start = (0, 0)
+--         ship0 = ShipW {positionW = start, waypoint = (10, 1) }
+--         ship1 = foldl actW ship0 actions
 
 act Ship{..} (N d) = Ship { position = dDelta d North position, ..}
 act Ship{..} (S d) = Ship { position = dDelta d South position, ..}
@@ -63,9 +63,7 @@ act Ship{..} (E d) = Ship { position = dDelta d East  position, ..}
 act Ship{..} (L a) = Ship { direction = d, ..} where d = (iterate predW direction) !! (a `div` 90)
 act Ship{..} (R a) = Ship { direction = d, ..} where d = (iterate succW direction) !! (a `div` 90)
 act Ship{..} (F d) = Ship { position = dDelta d direction position, ..} 
-  -- where (x, y) = position
-  --       (dx, dy) = (delta direction)
-  --       p' = (x + (d * dx), y + (d * dy))
+
 
 actW ShipW{..} (N d) = ShipW { waypoint = dDelta d North waypoint, ..}
 actW ShipW{..} (S d) = ShipW { waypoint = dDelta d South waypoint, ..}
diff --git a/advent13/package.yaml b/advent13/package.yaml
new file mode 100644
index 0000000..fde2277
--- /dev/null
+++ b/advent13/package.yaml
@@ -0,0 +1,62 @@
+# This YAML file describes your package. Stack will automatically generate a
+# Cabal file when you run `stack build`. See the hpack website for help with
+# this file: <https://github.com/sol/hpack>.
+
+name: advent13
+synopsis: Advent of Code
+version: '0.0.1'
+
+default-extensions:
+- AllowAmbiguousTypes
+- ApplicativeDo
+- BangPatterns
+- BlockArguments
+- DataKinds
+- DeriveFoldable
+- DeriveFunctor
+- DeriveGeneric
+- DeriveTraversable
+- EmptyCase
+- FlexibleContexts
+- FlexibleInstances
+- FunctionalDependencies
+- GADTs
+- GeneralizedNewtypeDeriving
+- ImplicitParams
+- KindSignatures
+- LambdaCase
+- MonadComprehensions
+- MonoLocalBinds
+- MultiParamTypeClasses
+- MultiWayIf
+- NamedFieldPuns
+- NegativeLiterals
+- NumDecimals
+# - OverloadedLists
+- OverloadedStrings
+- PartialTypeSignatures
+- PatternGuards
+- PatternSynonyms
+- PolyKinds
+- RankNTypes
+- RecordWildCards
+- ScopedTypeVariables
+- TemplateHaskell
+- TransformListComp
+- TupleSections
+- TypeApplications
+- TypeFamilies
+- TypeInType
+- TypeOperators
+- ViewPatterns
+
+executables:
+  advent13:
+    main: advent13.hs
+    source-dirs: src
+    dependencies:
+    - base >= 2 && < 6
+    - text
+    - attoparsec
+    - arithmoi
+    
\ No newline at end of file
diff --git a/advent13/src/advent13.hs b/advent13/src/advent13.hs
new file mode 100644
index 0000000..bb4117e
--- /dev/null
+++ b/advent13/src/advent13.hs
@@ -0,0 +1,66 @@
+-- import Debug.Trace
+
+import Data.Text (Text)
+-- import qualified Data.Text as T
+import qualified Data.Text.IO as TIO
+
+import Data.Attoparsec.Text
+-- import Data.Attoparsec.Combinator
+import Control.Applicative
+import Data.Maybe
+import Data.List
+import Math.NumberTheory.Moduli.Chinese
+
+
+
+main :: IO ()
+main = 
+  do  text <- TIO.readFile "data/advent13.txt"
+      let (timestamp, busses) = successfulParse text
+      print timestamp
+      print busses
+      print $ part1 timestamp busses
+      print $ part2 busses
+
+part1 timestamp maybeBusses = eBus * eTime
+  where busses = catMaybes maybeBusses
+        busDepartures = map (busAndTime timestamp) busses
+        (eBus, eTime) = head $ sortOn snd busDepartures
+
+part2 maybeBusses = b - a
+  where (a, b) = earliestGroup $ periodOffsets maybeBusses
+
+
+busAndTime timestamp period = (period, earliestDeparture timestamp period)
+
+earliestDeparture timestamp period = period - (timestamp `mod` period)
+
+periodOffsets :: [Maybe Integer] -> [(Integer, Integer)]
+periodOffsets maybeBusses = offsetBusses
+  where offsetMaybeBusses = zip [0..] maybeBusses
+        offsetJustBusses = filter (isJust . snd) offsetMaybeBusses
+        offsetBusses = map (\(o, b) -> (o, fromJust b)) offsetJustBusses
+
+
+earliestGroup :: [(Integer, Integer)] -> (Integer, Integer)
+earliestGroup offsetBusses = foldl1 chineseStep offsetBusses
+
+
+chineseStep (n1, m1) (n2, m2) = (n, m1 * m2)
+  where n = fromJust $ chinese (n1, m1) (n2, m2)
+
+
+-- Parse the input file
+
+timeBusP = (,) <$> decimal <* endOfLine <*> busPeriodsP
+
+busPeriodsP = busPeriodP `sepBy` (string ",")
+
+busPeriodP = (Just <$> decimal) <|> ("x" *> pure Nothing)
+
+
+successfulParse :: Text -> (Integer, [Maybe Integer])
+successfulParse input = 
+  case parseOnly timeBusP input of
+    Left  _err -> (0, []) -- TIO.putStr $ T.pack $ parseErrorPretty err
+    Right timeBus -> timeBus
diff --git a/data/advent13.txt b/data/advent13.txt
new file mode 100644
index 0000000..f569282
--- /dev/null
+++ b/data/advent13.txt
@@ -0,0 +1,2 @@
+1000104
+41,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,37,x,x,x,x,x,659,x,x,x,x,x,x,x,23,x,x,x,x,13,x,x,x,x,x,19,x,x,x,x,x,x,x,x,x,29,x,937,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,17
\ No newline at end of file
diff --git a/stack.yaml b/stack.yaml
index 33cb0a8..24a447e 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -47,6 +47,7 @@ packages:
 - advent10
 - advent11
 - advent12
+- advent13
 
 # Dependency packages to be pulled from upstream that are not in the resolver.
 # These entries can reference officially published versions as well as