application/vnd.lotus-screencam
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672 B
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22 lines
;; The biggest product of 2 3-digit numbers that is a palindrome
;; https://projecteuler.net/problem=4
(define (reverse-num a ret)
(if (< a 1)
ret
(reverse-num (floor (/ a 10))
(+ (* ret 10) (floor (modulo a 10))))))
(define (palindrome? a)
(= a (reverse-num a 0)))
(define (search a b ret)
(cond ((>= a 1000) ret)
((>= b 1000) (search (+ a 1) 0 ret))
(else (search a (+ 1 b) (if (palindrome? (* a b))
(max ret (* a b))
ret)))))
(display "The biggest product of 2 3-digit numbers that is a palindrome is: ")
(display (search 0 0 0))
(newline)
