数字之间的最小差异

Question

我们有K组不同的数字。我们必须从每组中选择一个数字，以便更高和更低数字之间的差值是最小值。

任何想法？

Answer 1

这样的事情（用Haskell写的）？

import Data.List (minimum, maximum, minimumBy) 

minDiff (x:xs) = comb (head x) (diff $ matches (head x)) x where 
    lenxs = length xs 
    diff m = maximum m - minimum m 
    matches y = minimumBy (\a b -> compare (diff a) (diff b)) $ p [] 0 where 
    md = map (minimumBy (\a b -> compare (abs (a - y)) (abs (b - y)))) xs 
    mds = [m | m <- foldl (\b a -> filter (\z -> abs (z - y) == abs (y - md!!a)) (xs!!a) : b) [] [0..lenxs - 1]] 
    p result index 
     | index == lenxs = [y:result] 
     | otherwise  = do 
      p' <- mds!!index 
      p (p':result) (index + 1) 
    comb result difference []  = matches result 
    comb result difference (z:zs) = 
    let diff' = diff (matches z) 
    in if diff' < difference 
      then comb z diff' zs 
      else comb result difference zs 


OUTPUT: 
*Main> minDiff [[1,3,5,9,10],[2,4,6,8],[7,11,12,13]] 
[5,6,7]