04/02/19 17:42
>>44
なるほど。
lengthを軽々しく使わないほうがいいのかもな。
じゃあ、こんなので
j num = map (take num) . filter (biggerOrEqual num) . tails
biggerOrEqual :: Int -> [a] -> Bool
biggerOrEqual 0 _ = True
biggerOrEqual n [] = False
biggerOrEqual n (x:xs) = biggerOrEqual (n-1) xs