X-Git-Url: https://git.njae.me.uk/?a=blobdiff_plain;f=app%2Fadvent01.hs;fp=app%2Fadvent01.hs;h=0000000000000000000000000000000000000000;hb=fd498a2713d69a5d55179ff07e58ce296d6fba94;hp=b76195dc7e6cde94c83c894c75b39c162422b49b;hpb=3a26b187d5dc23b05fb73daabe52a92976a7a3c7;p=advent-of-code-16.git

diff --git a/app/advent01.hs b/app/advent01.hs
deleted file mode 100644
index b76195d..0000000
--- a/app/advent01.hs
+++ /dev/null
@@ -1,99 +0,0 @@
-module Main(main) where
-
-import Data.List (sort)
-import Data.List.Split (splitOn)
-
--- turn direction, number of steps
-data Step = Step Char Int deriving (Show)
-
-data Direction = North | East | South | West 
-    deriving (Enum, Show, Bounded, Eq)
-
--- direction, easting, northing
-data Position = Position Direction Int Int deriving (Show)
--- Two positions are the same if they're in the same place, 
--- regardless of facing
-instance Eq Position where
-    Position _ e n == Position _ e' n' = e == e' && n == n'
-
-main :: IO ()
-main = do 
-        instructions <- readFile "data/advent01.txt"
-        part1 instructions
-        part2 instructions
-
-part1 :: String -> IO ()
-part1 instructions = do
-        let answer = finalDistance $ last $ stepsFromStart $ steps instructions
-        print answer
-
-part2 :: String -> IO ()
-part2 instructions = do
-        let visited = finalDistance $ firstRepeat $ stepsFromStart $ expandSteps $ steps instructions
-        print visited
-
-
--- Extract the steps from the input string.
-steps :: String -> [Step]
-steps s = map readStep $ splitOn ", " s
-    where readStep (d:l) = Step d (read l)
-
--- Take steps from the starting position
-stepsFromStart :: [Step] -> [Position]
-stepsFromStart = takeSteps (Position North 0 0)
-
--- Calculate manhattan distance from start to this state
-finalDistance :: Position -> Int
-finalDistance (Position _ e n) = (abs e) + (abs n)
-
--- For part 2: convert one step of many spaces to many steps of one space each
-expandSteps :: [Step] -> [Step]
-expandSteps = 
-    concatMap expandStep
-    where expandStep (Step dir d) = (Step dir 1) : replicate (d - 1) (Step 'S' 1)
-
--- Execute a series of steps, keeping track of the positions after each step
-takeSteps :: Position -> [Step] -> [Position]
--- takeSteps pos steps = scanl move pos steps
-takeSteps = scanl move
-
--- Make one move, by updating direction then position
-move :: Position -> Step -> Position
-move (Position facing easting northing)
-    (Step turnInstr distance) = 
-    Position facing' easting' northing'
-    where facing' = turn turnInstr facing
-          (easting', northing') = takeStep facing' distance easting northing
-
--- Turn right, left, or straight
-turn :: Char -> Direction -> Direction
-turn 'R' direction = turnCW direction
-turn 'L' direction = turnACW direction
-turn 'S' direction = direction
-
--- Move in the current direction
-takeStep :: Direction -> Int -> Int -> Int -> (Int, Int)
-takeStep North d e n = (e, n+d)
-takeStep South d e n = (e, n-d)
-takeStep West  d e n = (e-d, n)
-takeStep East  d e n = (e+d, n)
-
-
--- | a `succ` that wraps 
-turnCW :: (Bounded a, Enum a, Eq a) => a -> a 
-turnCW dir | dir == maxBound = minBound
-         | otherwise = succ dir
-
--- | a `pred` that wraps
-turnACW :: (Bounded a, Enum a, Eq a) => a -> a
-turnACW dir | dir == minBound = maxBound
-            | otherwise = pred dir
-
--- All the prefixes of a list of items
-prefixes = scanl addTerm []
-    where addTerm ps t = ps ++ [t]
-
--- The first item that exists in a prefix of the list to that point
-firstRepeat positions = 
-    last $ head $ dropWhile (\p -> (last p) `notElem` (tail $ reverse p)) 
-                            (tail $ prefixes positions)