AoC/2019/day9/day9.hs
2019-12-09 17:35:34 +01:00

83 lines
3.6 KiB
Haskell

import Data.List.Split
import Data.List as L
import Data.Vector as V hiding ((++), concatMap, map, elem, last, head, length, splitAt, reverse)
import qualified Data.Vector as V ((++), last)
import Data.Char
import Control.DeepSeq as DeepSeq
data OutAction = Continue | Output | Halt deriving (Enum, Eq, Show)
data Mode = Position | Immediate | Relative deriving (Enum, Eq, Show)
type Tape = Vector Integer
type TapeSection = Vector Integer
type TuringMachine = (Tape,Integer,Integer)
main = do
content <- readFile "input"
let tape = fromList $ concatMap (map read . splitOn ",") (lines content)
let run x = execSteps ((tapePreprocess tape,0,0),[x],[],Continue)
let (_,_,out1,_) = run 1
let (_,_,out2,_) = run 2
print $ L.concat ["Part 1: " ++ show a ++ ", Part 2: " ++ show b | a<-out1,b<-out2]
tapePreprocess :: TapeSection -> TapeSection
tapePreprocess t = (V.++) t $ V.replicate 105 0
opLength :: Integer -> Integer
opLength x
| n`elem`"1278"=4
| n`elem`"56"=3
| n`elem`"349"=2
| otherwise=1
where n = last $ show x
parseModes :: String -> [Mode]
parseModes m = L.replicate (3 - length l) Position ++ l
where l = map (toEnum . digitToInt) m
paramChange :: [Mode] -> Integer -> TapeSection -> Tape -> TapeSection
paramChange m rbase opvec t = imap f (V.tail opvec)
where f i a = case m !! i of
Immediate -> a
Position -> t ! fromInteger a
Relative -> t ! fromInteger (a + rbase)
getOpModes :: TapeSection -> (String, [Mode])
getOpModes opvec = (op_dedup,parsed_modes)
where (op,modes) = splitAt 2 $ reverse $ show $ opvec ! 0
parsed_modes = reverse $ parseModes $ reverse modes
op_dedup = if last op == '0' then [head op] else op
step :: TapeSection -> (TuringMachine, [Integer], [Integer]) -> (TuringMachine, OutAction, [Integer], [Integer])
step opvec ((t,p,rbase),input,output) = case op of
"1" -> (tm_binop (+),Continue,input,output)
"2" -> (tm_binop (*),Continue,input,output)
"3" -> (new_tm t $ head input,Continue,L.tail input,output)
"4" -> ((t,p,rbase),Output,input,V.last params:output)
"5" -> ((t, if params ! 0/=0 then params ! 1 else p,rbase),Continue,input,output)
"6" -> ((t, if params ! 0==0 then params ! 1 else p,rbase),Continue,input,output)
"7" -> (tm_binop (\x y->if x<y then 1 else 0),Continue,input,output)
"8" -> (tm_binop (\x y->if x==y then 1 else 0),Continue,input,output)
"9" -> ((t,p,rbase + (params ! 0)),Continue,input,output)
"99" -> ((t,p,rbase),Halt,input,output)
where (op,m) = getOpModes opvec
params = paramChange m rbase opvec t
tm_binop x = new_tm t ((params ! 0) `x` (params ! 1))
{-without the following DeepSeq call, thunks build up eternally
and the vectors won’t be garbage collected: >4GB RAM usage,
god knows how much with large vectors, now ~20mB-}
new_tm t x = DeepSeq.force (t // [(target, x)],p,rbase)
target = fromInteger $ case m !! (length params -1) of
Relative -> V.last opvec + rbase
_ -> V.last opvec
execSteps :: (TuringMachine, [Integer], [Integer], OutAction) -> (TuringMachine, [Integer], [Integer], OutAction)
execSteps ((t,p,rbase),input,output,halt) =
let command_length = opLength $! t ! fromInteger p
opvec = slice (fromInteger p) (fromInteger command_length) t
((t_new,p_new,rbase_new),cond,input_new,output_new) =
step opvec ((t,p+command_length,rbase),input,output) in
case cond of
Halt -> ((t_new,p_new,rbase_new),input_new,output_new,cond)
_ -> execSteps ((t_new,p_new,rbase_new),input_new,output_new,cond)