From: Neil Smith <neil.git@njae.me.uk>
Date: Tue, 3 Dec 2019 09:13:19 +0000 (+0000)
Subject: Done day 3 part 1
X-Git-Url: https://git.njae.me.uk/?p=advent-of-code-19.git;a=commitdiff_plain;h=9ae9e4b2751996170400ddea8503a3b0313e724c

Done day 3 part 1
---

diff --git a/advent03/package.yaml b/advent03/package.yaml
new file mode 100644
index 0000000..2706725
--- /dev/null
+++ b/advent03/package.yaml
@@ -0,0 +1,61 @@
+# 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: advent03
+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
+- NegativeLiterals
+- NumDecimals
+- OverloadedLists
+- OverloadedStrings
+- PartialTypeSignatures
+- PatternGuards
+- PatternSynonyms
+- PolyKinds
+- RankNTypes
+- RecordWildCards
+- ScopedTypeVariables
+- TemplateHaskell
+- TransformListComp
+- TupleSections
+- TypeApplications
+- TypeInType
+- TypeOperators
+- ViewPatterns
+
+
+executables:
+  advent03:
+    main: advent03.hs
+    source-dirs: src
+    dependencies:
+    - base >= 2 && < 6
+    - text
+    - megaparsec
+    - containers
+    - linear
diff --git a/advent03/src/advent03.hs b/advent03/src/advent03.hs
new file mode 100644
index 0000000..a541f23
--- /dev/null
+++ b/advent03/src/advent03.hs
@@ -0,0 +1,113 @@
+-- Some code taken from [AoC 2017 day 5](https://adventofcode.com/2017/day/5), 
+--    and some from [AoC 2018 day 21](https://adventofcode.com/2018/day/21)
+
+import Data.Text (Text)
+import qualified Data.Text.IO as TIO
+
+import Data.Void (Void)
+
+import Text.Megaparsec hiding (State)
+import Text.Megaparsec.Char
+import qualified Text.Megaparsec.Char.Lexer as L
+import qualified Control.Applicative as CA
+
+import Data.List (foldl')
+import qualified Data.Set as S
+
+import Linear (V2(..), (^+^), (^-^), (*^), (*^))
+
+data Direction = East | South | West | North deriving (Show, Eq)
+
+type Location = V2 Int -- x, y
+
+type Visited = S.Set Location
+
+data Path = Path { _visited :: Visited
+                 , _tip :: Location
+                 } 
+               deriving (Show, Eq)
+
+data Segment = Segment { _direction :: Direction
+                       , _steps :: Int
+                       } deriving (Show, Eq)
+
+
+main :: IO ()
+main = do 
+        text <- TIO.readFile "data/advent03.txt"
+        let segmentss = successfulParse text
+        print segmentss
+        -- print $ travelPath $ head segmentss
+        print $ part1 segmentss
+        -- print $ part2 machine
+
+part1 :: [[Segment]] -> Int
+part1 segmentss = closest $ crossovers $ travelAllPaths segmentss
+
+closest :: Visited -> Int
+closest points = S.findMin $ S.map manhattan points
+
+crossovers :: [Path] -> Visited
+crossovers travelledPaths = 
+      foldl' S.intersection
+             (_visited $ head travelledPaths)
+             (map _visited $ drop 1 travelledPaths)
+
+travelAllPaths :: [[Segment]] -> [Path]
+travelAllPaths = map travelPath
+
+travelPath :: [Segment] -> Path
+travelPath segments = foldl' travelSegment path0 segments
+    where   path0 = Path { _visited = S.empty, _tip = V2 0 0 }
+
+travelSegment :: Path -> Segment -> Path
+travelSegment path segment = path { _tip = tip', _visited = visited' }
+    where   delta = facing $ _direction segment
+            distance = _steps segment
+            start = _tip path
+            visited = _visited path
+            visited' = foldl' (flip S.insert) visited $ take distance $ drop 1 $ iterate (^+^ delta) start
+            tip' = start ^+^ distance *^ delta
+
+facing :: Direction -> Location
+facing East = V2 1 0
+facing South = V2 0 (-1)
+facing West = V2 (-1) 0
+facing North = V2 0 1
+
+
+manhattan (V2 x y) = (abs x) + (abs y)
+
+-- Parse the input file
+type Parser = Parsec Void Text
+
+sc :: Parser ()
+sc = L.space (skipSome spaceChar) CA.empty CA.empty
+-- sc = L.space (skipSome (char ' ')) CA.empty CA.empty
+
+lexeme  = L.lexeme sc
+integer = lexeme L.decimal
+-- signedInteger = L.signed sc integer
+symb = L.symbol sc
+comma = symb ","
+
+wiresP = some pathP
+pathP = segmentP `sepBy1` comma
+
+segmentP = segmentify <$> directionP <*> integer
+    where segmentify direction steps = 
+              Segment { _direction = direction, _steps = steps }
+
+
+directionP = eP <|> sP <|> wP <|> nP
+eP = (symb "R" *> pure East)
+sP = (symb "D" *> pure South)
+wP = (symb "L" *> pure West)
+nP = (symb "U" *> pure North)
+
+
+successfulParse :: Text -> [[Segment]]
+successfulParse input = 
+        case parse wiresP "input" input of
+                Left  _err -> [] -- TIO.putStr $ T.pack $ parseErrorPretty err
+                Right wires -> wires
\ No newline at end of file
diff --git a/data/advent03.txt b/data/advent03.txt
new file mode 100644
index 0000000..81e0841
--- /dev/null
+++ b/data/advent03.txt
@@ -0,0 +1,2 @@
+R1003,U756,L776,U308,R718,D577,R902,D776,R760,U638,R289,D70,L885,U161,R807,D842,R175,D955,R643,U380,R329,U573,L944,D2,L807,D886,L549,U592,R152,D884,L761,D915,L726,D677,L417,D651,L108,D377,L699,D938,R555,D222,L689,D196,L454,U309,L470,D234,R198,U689,L996,U117,R208,D310,R572,D562,L207,U244,L769,U186,R153,D756,R97,D625,R686,U244,R348,U586,L385,D466,R483,U718,L892,D39,R692,U756,L724,U148,R70,U224,L837,D370,L309,U235,R382,D579,R404,D146,R6,U584,L840,D863,R942,U646,R146,D618,L12,U210,R126,U163,R931,D661,L710,D883,L686,D688,L148,D19,R703,U530,R889,U186,R779,D503,R417,U272,R541,U21,L562,D10,L349,U998,R69,D65,R560,D585,L949,D372,L110,D865,R212,U56,L936,U957,L88,U612,R927,U642,R416,U348,L541,D416,L808,D759,R449,D6,L517,D4,R494,D143,L536,U341,R394,U179,L22,D680,L138,U249,L285,U879,L717,U756,L313,U222,R823,D208,L134,U984,R282,U635,R207,D63,L416,U511,L179,D582,L651,U932,R646,U378,R263,U138,L920,U523,L859,D556,L277,D518,R489,U561,L457,D297,R72,U920,L583,U23,L395,D844,R776,D552,L55,D500,R111,U409,R685,D427,R275,U739,R181,U333,L215,U808,R341,D537,R336,U230,R247,U748,R846,U404,R850,D493,R891,U176,L744,U585,L987,D849,R271,D848,L555,U801,R316,U753,L390,U97,L128,U45,R706,U35,L928,U913,R537,D512,R152,D410,R76,D209,R183,U941,R289,U632,L923,D190,R488,D934,R442,D303,R178,D250,R204,U247,R707,U77,R428,D701,R386,U110,R641,U925,R703,D387,L946,U415,R461,D123,L214,U236,L959,U517,R957,D524,R812,D668,R369,U340,L606,D503,R755,U390,R142,D921,L976,D36,L965,D450,L722,D224,L303,U705,L584
+L993,U810,L931,D139,R114,D77,L75,U715,R540,D994,L866,U461,R340,D179,R314,D423,R629,D8,L692,U446,L88,D132,L128,U934,L465,D58,L696,D883,L955,D565,R424,U286,R403,U57,L627,D930,R887,D941,L306,D951,R918,U587,R939,U821,L65,D18,L987,D707,L360,D54,L932,U366,R625,U609,R173,D637,R661,U888,L68,U962,R270,U369,R780,U845,L813,U481,R66,D182,R420,U605,R880,D276,L6,D529,R883,U189,R380,D472,R30,U35,L510,D844,L146,U875,R152,U545,R274,U920,R432,U814,R583,D559,L820,U135,L353,U975,L103,U615,R401,U692,L676,D781,R551,D985,L317,U836,R115,D216,L967,U286,R681,U144,L354,U678,L893,D487,R664,D185,R787,D909,L582,D283,L519,D893,L56,U768,L345,D992,L248,U439,R573,D98,L390,D43,L470,D435,R176,U468,R688,U388,L377,U800,R187,U641,L268,U857,L716,D179,R212,U196,L342,U731,R261,D92,R183,D623,L589,D215,L966,U878,L784,U740,R823,D99,L167,D992,R414,U22,L27,U390,R286,D744,L360,U554,L756,U715,R939,D806,R279,U292,L960,U633,L428,U949,R90,D321,R749,U395,L392,U348,L33,D757,R289,D367,L562,D668,L79,D193,L991,D705,L562,U25,R146,D34,R325,U203,R403,D714,R607,U72,L444,D76,R267,U924,R289,U962,L159,U726,L57,D540,R299,U343,R936,U90,L311,U243,L415,D426,L936,D570,L539,D731,R367,D374,L56,D251,L265,U65,L14,D882,L956,U88,R688,D34,R866,U777,R342,D270,L344,D953,L438,D855,L587,U320,L953,D945,L473,U559,L487,D602,R255,U871,L854,U45,R705,D247,R955,U885,R657,D664,L360,D764,L549,D676,R85,U189,L951,D922,R511,D429,R37,U11,R821,U984,R825,U874,R753,D524,L537,U618,L919,D597,L364,D231,L258,U818,R406,D208,R214,U530,R261
\ No newline at end of file
diff --git a/stack.yaml b/stack.yaml
index 9de915b..1b3c906 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -39,6 +39,7 @@ packages:
 # - .
 - advent01
 - advent02
+- advent03
 
 
 # Dependency packages to be pulled from upstream that are not in the resolver.