euler004.clj

; Problem 4
; A palindromic number reads the same both ways. The largest
; palindrome made from the product of two 2-digit numbers
; is 9009 = 91  99.
;
; Find the largest palindrome made from the product of two 3-digit numbers.

(defn palindromic? [x]
  (let [strx (str x)]
    (= (seq strx) (reverse strx))))

(def pals
     (filter #(not (empty? %))
	     (for [x (range 100 1000)]
	       (filter #(palindromic? (last %))
		       (for [y (range x 1000)]
			 [x y (* x y)])))))

(def largest 
     (last
      (first (sort #(> (last %1) (last %2)) (map last pals)))))