module Exercise_6 where

import Data.Ratio
import Data.Maybe
import Data.List

{-WETT-}

traceFractran :: [Rational] -> Integer -> [Integer]
traceFractran fs n = n:if null nfs then nfs else fs `traceFractran` head nfs
    where   ni = fromIntegral n
            nfs = [numerator $ f*ni | f <- fs, 1 == denominator (f*ni)]
{-TTEW-}
-- traceFractran :: [Rational] -> Integer -> [Integer]
-- traceFractran fs n = n:if isNothing mf then [] else traceFractran fs (numerator $ ni*fromJust mf)
--     where   ni = fromIntegral n
--             mf = find (\f -> 1 == denominator $ f*ni) fs
--

-- isPowerOfTwo 1 = True
-- isPowerOfTwo n = n `mod` 2 == 0 && isPowerOfTwo (div n 2)
-- primeprog = [17%91 ,78%85 ,19%51 ,23%38 ,29%33 ,77%29 ,95%23 ,77%19 ,1%17 , 11%13 ,13%11 ,15%14 ,15%2 ,55%1]