subSeries.hs

import Data.List
import Data.Ord
import Test.QuickCheck
import Test.HUnit

getSubSeries :: [Int] -> Int -> [Int]
getSubSeries [] _ = []
getSubSeries series threshold = head [x | x <- sortBy (flip $ comparing length) $ subLists series, 
                                          sum x <= threshold]
                                where 
                                    subLists xs = ( ([] :) . concatMap (tail . inits) . tails) xs

testSeries :: [Int]
testSeries = [100, 300, 100, 50, 50, 50, 50, 50, 500, 200, 100]

-- QuickCheck general property: any result must be a sub-list of the original list
-- Load in GHCI:
-- quickCheck prop_getSubSeries_1
prop_getSubSeries_1 :: [Int] -> Bool
prop_getSubSeries_1 xs = getSubSeries xs 500 `isInfixOf` xs

-- Test Case
test1 :: Test
test1 = TestCase (assertEqual "test1" (getSubSeries testSeries 500) [100, 50, 50, 50, 50, 50])
tests :: Test
tests = TestList [TestLabel "test1" test1]