4clojure 题解 Palindrome Detector

经典的回文判断问题

Write a function which returns true if the given sequence is a palindrome.

Hint: "racecar" does not equal '(\r \a \c \e \c \a \r)

	(false? (__ '(1 2 3 4 5)))
	(true? (__ "racecar"))
	(true? (__ [:foo :bar :foo]))
	(true? (__ '(1 1 3 3 1 1)))
	(false? (__ '(:a :b :c)))

(fn [all]
   (let [rev (reverse all)
         len (count all)
         flen (inc (int (/ len 2)))]
     (every? true? (map (fn [x]
                          (= (nth rev x)
                              (nth all x))
                          ) (range flen)))
     )
   )