a job interview task solution

job-candidate-selection.haskell

-- preliminaries

type Score = Integer
type SkillSet = Array Score
newtype Salary = WrapSalary { unwrapSalary :: Integer {-^ HUF / month -} }
	deriving (Ord)

data Candidate = Candidate
{
	name :: String,
	skill_set :: SkillSet,
	salary_demand :: Salary
}


-- the selection algorithm

-- | computes the candidates best according to the given evluation function
select_best :: Ord score => (e -> score) -> List e -> List e
select_best evaluation = 
	let 
		best_score = map second >>> min
		select_with_score_at_least s = filter (second >>> (>= s)) >>> map first
	in 
		map (id &&& evaluation) >>> 
		(select_with_score_at_least &&& best_score) >>>
		(=<<) >>> concat

select_candidate :: List Candidate -> Maybe Candidate
select_candidate = select_best (skill_set >>> fold) >>> minBy salary_demand