Help us understand the problem. What is going on with this article?


More than 5 years have passed since last update.



import Data.List

type Path = (Char,Char)
type Graph = [Path]
graph = [
        ] :: Graph

makeGraph :: IO Graph
makeGraph = do
    line <- getLine
    let removedPath = concatMap (\(x:y:[]) -> [(x,y),(y,x)]) $ words line
    let removedGraph = foldr delete graph removedPath
    return removedGraph

dfs p g graph px | p == g = 1
                 | p `elem` px = 0
                 | otherwise = sum [dfs np g graph (p:px) | np <- nextp p]
                    nextp p = [y | (x,y) <- graph, x == p]

main = do
    removedGraph <- makeGraph
    print $ dfs 'a' 'y' removedGraph []


Why not register and get more from Qiita?
  1. We will deliver articles that match you
    By following users and tags, you can catch up information on technical fields that you are interested in as a whole
  2. you can read useful information later efficiently
    By "stocking" the articles you like, you can search right away