module Exercise_8 where

import Data.List

{-WETT-}
shoefa :: (Num a, Ord a) => [a] -> Int

shoefa xs = if null f then 0 else pred $ length $ group $ map signum f
            where f = filter (/=0) xs

-- shoefa xs = length $ groupBy (<) $ map signum $ filter (/=0) xs
-- shoefaTest xs = groupBy (<) $ map signum $ filter (/=0) xs

--  Token
-- shoefa [] = 0
-- shoefa xs = fst $ foldl (\acc s -> if snd acc == s then acc else (1+fst acc, snd acc) ) (0,head nums) nums
            -- where
                    -- nums = [signum x |x <- xs, 0 /= signum x]    

--  Token
-- shoefa [] = 0                   
-- shoefa xs = fst $ foldl (\(i,p) s -> if p == s then (i,p) else (i+1, s) ) (0,head nums) nums
            -- where
                    -- nums = [signum x |x <- xs, 0 /= signum x]

--  Token
-- shoefa [] = 0
-- shoefa xs = shoefaRec nums $signum $head nums 
            -- where
                    -- nums = [signum x |x <- xs, 0 /= signum x]
                    -- shoefaRec [] _ = 0
                    -- shoefaRec (x:xs) prev = if (prev == x)
                                            -- then 0 + shoefaRec xs prev
                                            -- else 1 + shoefaRec xs x

-- Case [0,1] fail
-- shoefa [] = 0
-- shoefa xs = shoefaRec xs $signum $head xs 
            -- where 
                    -- shoefaRec [] _ = 0
                    -- shoefaRec (x:xs) prev = if prev == signum x || 0 == signum x
                                            -- then 0 + shoefaRec xs prev
                                            -- else 1 + shoefaRec xs prev

{-TTEW-}