以下是 Haskell 代码，我100%确定能通过数据点，为啥线上提交输出是0呢？

{-# LANGUAGE LambdaCase #-}
module Main where

import           Control.Arrow
import           Control.Monad.ST
import           Data.Foldable       (for_)
import qualified Data.HashMap.Strict as HM
import           Data.IORef

readTape :: IO [(Int, Int)]
readTape = do
    numbers <- fmap read . words <$> getLine
    colors <- fmap read . words <$> getLine
    return $ zip colors numbers

-- | return odd colors, even colors (pos, number)
readTape' :: IO (HM.HashMap Int [(Int, Int)], HM.HashMap Int [(Int, Int)])
readTape' = do
    oddm <- newIORef HM.empty
    evenm <- newIORef HM.empty
    tapes <- readTape
    for_ (zip [1..] tapes) $ \(index, (color, number)) -> modifyIORef (if odd index then oddm else evenm) $ \m ->
        HM.alter (\case
                    Just xs -> return $ (index, number) : xs
                    Nothing -> return [(index, number)]
        ) color m
    o <- readIORef oddm
    e <- readIORef evenm
    return (o, e)

calculateScore :: (HM.HashMap Int [(Int, Int)], HM.HashMap Int [(Int, Int)]) -> Int
calculateScore (oddm, evenm) = (sum (map (sumUp . snd) $ HM.toList oddm) + sum (map (sumUp . snd) $ HM.toList evenm)) `mod` 10007
    where sumUp :: [(Int, Int)] -> Int
          sumUp m = foldl (\x (a, b) -> (x + b * (a * (n - 2) + posSum)) `mod` 10007) 0 m
            where posSum = sum $ fst <$> m
                  n = length m

main :: IO ()
main = print . calculateScore =<< readTape'