生測資

banana.hs

import Control.Monad (mapM_)
import System.Random
import System.Cmd
import System.Environment (getArgs)
import Data.List (intercalate, nub)

type Size = Int
type Constraint = (Variable, Variable)
data Variable = Variable Int deriving (Eq)
data Map = Map Size Size [Constraint]

instance Show Variable where
    show (Variable n) = "V" ++ show n 

instance Show Map where
    show (Map v c p) = "4 " ++ show v ++ " " ++ show c ++ "\n" ++ variables ++ "\n" ++ pairs
        where   variables = intercalate " " $ map (show . Variable) [0 .. pred v]
                pairs = intercalate "\n" $ map (\(a, b) -> show a ++ " " ++ show b) p

color = 4

constraints :: Size -> Int -> [Constraint]
constraints numberOfVariables seed = nub . take numberOfConstraints . map pickConstraint $ randomRs (0, upperBound - 1) gen'
    where   gen = mkStdGen seed
            (numberOfConstraints, gen') = randomR (0, upperBound) gen
            upperBound = (numberOfVariables - 1) * numberOfVariables `div` 2
            pickConstraint = (!!) (constraintPairs numberOfVariables)
            constraintPairs n = [ (Variable a, Variable b) | a <- [0..pred n], b <- [0..pred n], a < b]


makeMap seed n = Map n (length pairs) pairs
    where   pairs = constraints n seed

genTest n = return $ map (makeMap 40) [0..n]
writeMap m = writeFile ("test" ++ show size ++ ".txt") (show m)
    where   (Map size _ _) = m

main = do
    fmap (read . head) getArgs >>= genTest >>= mapM_ writeMap