48 lines
1.7 KiB
Haskell
48 lines
1.7 KiB
Haskell
|
import Aoc
|
||
|
|
import Data.Char ( isDigit )
|
||
|
|
import Data.Bits
|
||
|
|
|
||
|
|
data Op = AND | OR | SHIFTL | SHIFTR | NOT | CONST
|
||
|
|
deriving (Show, Eq)
|
||
|
|
|
||
|
|
parseFile :: [String] -> [(String, (Op, String, String))] -- [(out, (op, arg1, arg2))]
|
||
|
|
parseFile = map (\line ->
|
||
|
|
let (expr, ["->", out]) = lastSplit 2 $ words line in
|
||
|
|
(out, case expr of
|
||
|
|
[arg1, "AND", arg2] -> (AND, arg1, arg2)
|
||
|
|
[arg1, "OR", arg2] -> (OR, arg1, arg2)
|
||
|
|
[arg1, "LSHIFT", arg2] -> (SHIFTL, arg1, arg2)
|
||
|
|
[arg1, "RSHIFT", arg2] -> (SHIFTR, arg1, arg2)
|
||
|
|
["NOT", arg] -> (NOT, arg, "")
|
||
|
|
[arg] -> (CONST, arg, "")))
|
||
|
|
|
||
|
|
eval :: Op -> Int -> Int -> Int
|
||
|
|
eval OR = (.|.)
|
||
|
|
eval AND = (.&.)
|
||
|
|
eval SHIFTR = shiftR
|
||
|
|
eval SHIFTL = shiftL
|
||
|
|
eval CONST = const
|
||
|
|
eval NOT = \a _-> complement a
|
||
|
|
|
||
|
|
eval' :: Op -> Int -> Int -> Int
|
||
|
|
eval' op arg1 arg2 = (.&. 0xFFFF) $ eval op arg1 arg2
|
||
|
|
|
||
|
|
eval'' :: [(String, (Op, String, String))] -> [(String, Int)] -> String -> (Int, [(String, Int)])
|
||
|
|
eval'' wires memos label = case lookup label memos of
|
||
|
|
Just value -> (value, memos)
|
||
|
|
Nothing -> case lookup label wires of
|
||
|
|
Just (op, arg1, arg2) ->
|
||
|
|
let (val1, memos1) = eval'' wires memos arg1 in
|
||
|
|
let (val2, memos2) = eval'' wires memos1 arg2 in
|
||
|
|
let val = eval' op val1 val2 in
|
||
|
|
(val, (label, val):memos2)
|
||
|
|
Nothing -> (if all isDigit label then read label else undefined, memos) -- if null label then 0 else
|
||
|
|
|
||
|
|
part1 :: [(String, (Op, String, String))] -> Int
|
||
|
|
part1 wires = fst $ eval'' wires [] "a"
|
||
|
|
|
||
|
|
part2 :: [(String, (Op, String, String))] -> Int -> Int
|
||
|
|
part2 wires part1Answer = fst $ eval'' wires [("b", part1Answer)] "a"
|
||
|
|
|
||
|
|
main :: IO ()
|
||
|
|
main = aocMain' parseFile (passthrough . part1) part2
|