99 questions/Solutions/6
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(*) Find out whether a list is a palindrome. A palindrome can be read forward or backward; e.g. (x a m a x).
isPalindrome :: (Eq a) => [a] -> Bool
isPalindrome xs = xs == (reverse xs)
isPalindrome' [] = True
isPalindrome' [_] = True
isPalindrome' xs = (head xs) == (last xs) && (isPalindrome' $ init $ tail xs)
Here's one to show it done in a fold just for the fun of it. Do note that it is less efficient then the previous 2 though.
isPalindrome'' :: (Eq a) => [a] -> Bool
isPalindrome'' xs = foldl (\acc (a,b) -> if a == b then acc else False) True input --just to be different
where
input = zip xs (reverse xs)