import Data.List.Split (splitOn)
import Data.Map (Map)
import qualified Data.Map as Map

exec :: [[Char]] -> Int -> Map Char Int -> Int
exec rom addr regs
  | op == "snd" = exec rom (addr + 1) (Map.insert '_' dval regs)
  | op == "set" = exec rom (addr + 1) (Map.insert dest val regs)
  | op == "add" = exec rom (addr + 1) (Map.insert dest (dval + val) regs)
  | op == "mul" = exec rom (addr + 1) (Map.insert dest (dval * val) regs)
  | op == "mod" = exec rom (addr + 1) (Map.insert dest (dval `mod` val) regs)
  | op == "jgz" = exec rom (if dval > 0 then addr + val else addr + 1) regs
  | op == "rcv" = if dval /= 0 then regs Map.! '_' else exec rom (addr + 1) regs
      where ins = rom !! addr
            op:[dest]:xs = splitOn " " ins
            dval = regs Map.! dest
            x = head xs
            val = if head x `elem` alphabet then regs Map.! (head x) else read x

alphabet = ['a'..'z']

initRegs :: Map Char Int
initRegs = Map.fromList $ zipWith (,) ['a'..'z'] (cycle [0])

solve1 :: [Char] -> Int
solve1 xs = exec (splitOn "\n" xs) 0 initRegs

input0 = "set a 1\nadd a 2\nmul a a\nmod a 5\nsnd a\nset a 0\nrcv a\njgz a -1\nset a 1\njgz a -2"

input = "set i 31\nset a 1\nmul p 17\njgz p p\nmul a 2\nadd i -1\njgz i -2\nadd a -1\nset i 127\nset p 464\nmul p 8505\nmod p a\nmul p 129749\nadd p 12345\nmod p a\nset b p\nmod b 10000\nsnd b\nadd i -1\njgz i -9\njgz a 3\nrcv b\njgz b -1\nset f 0\nset i 126\nrcv a\nrcv b\nset p a\nmul p -1\nadd p b\njgz p 4\nsnd a\nset a b\njgz 1 3\nsnd b\nset f 1\nadd i -1\njgz i -11\nsnd a\njgz f -16\njgz a -19"