http://mtsmfm.github.io/2017/11/04/doukaku-e19.html のHaskellによる解答例

doukakuE19.hs

module Lib where

import Data.List.Split
import Data.List

solve :: String -> String
solve = intercalate "|" . map (intercalate "," . map show) . solve' . splitOn "," 

solve' :: [String] -> [[Int]]
solve' [p1,p2] = [a ++ b | a <- nub $ calc 0 ns p1 , let b = ns \\ a , calc 0 b p2 /= [] ]
    where
        len = length p1
        ns = sort ([1..len]++[1..len])
solve' _ = error "solve'"

calc :: Int -> [Int] -> String -> [[Int]]
calc _ _ [] = [[]]
calc _ [] _ = []
calc n xs (c:cs) = [y:ys | y:xs' <- tails xs , if c == 'x' then even y else odd y , n <= y , ys <- calc y xs' cs ]