# Bagley shootout. Was: Lightningspeed haskell

**Jan Kort
**
kort@wins.uva.nl

*Tue, 06 Mar 2001 11:04:22 +0100*

I implemented the programs for hash1 and hash2, but I had to
make a lot of changes to FiniteMap to get them to work:
- I changed foldl to foldl' (as defined in Hugs).
- I made foldFM strict (like foldl').
- I made the datatype FiniteMap strict (put !'s everywhere).
I put the programs below, maybe there is a better way to do this.
Jan
-- Hash1
module Main(main) where
import FiniteMap
import System
writeHex' :: Int -> String
writeHex' 0 = ""
writeHex' n
= c:writeHex' y
where
x = n `mod` 16
y = n `div` 16
c | x <= 9 = toEnum ((fromEnum '0') + x)
| otherwise = toEnum ((fromEnum 'A') + x - 10)
writeHex :: Int -> String
writeHex n
| n > 0 = reverse (writeHex' n)
| n == 0 = "0"
| otherwise = '-':(reverse (writeHex' (-n)))
main :: IO()
main = do {
[arg] <- getArgs;
let
n = read arg
fm = listToFM [(writeHex i,i) | i <- [1..n]]
c = sum [if elemFM (show i) fm then 1 else 0 | i <- reverse [1..n]]
in
putStrLn (show c);
-- Hash2
module Main(main) where
import FiniteMap
import System
import Maybe
foldl' :: (a -> b -> a) -> a -> [b] -> a
foldl' _ a [] = a
foldl' f a (x:xs) = (foldl' f $! f a x) xs
f :: FiniteMap Int Int -> FiniteMap Int Int -> Int -> FiniteMap Int Int
f hash1 hash2 k
| isJust elt2 = addToFM hash2 k (fromJust elt1 + fromJust elt2)
| otherwise = addToFM hash2 k (fromJust elt1)
where
elt1 = lookupFM hash1 k
elt2 = lookupFM hash2 k
main :: IO()
main = do {
[arg] <- getArgs;
let
n = read arg
hash1 = listToFM [(i,i) | i <- [1..10000]]
keys = concat (take n (repeat (keysFM hash1)))
hash2 = foldl' (f hash1) emptyFM keys;
h1_1 = fromJust (lookupFM hash1 1)
h1_9999 = fromJust (lookupFM hash1 9999)
h2_1 = fromJust (lookupFM hash2 1)
h2_9999 = fromJust (lookupFM hash2 9999)
in
putStrLn (show h1_1 ++ " " ++ show h1_9999 ++ " " ++
show h2_1 ++ " " ++ show h2_9999);
}