Nerd Stuff

(require-extension srfi-13) (require-extension extras) (define-record palindromic steps palindrome) (define (is-palindrome? n) (let* ((n-forwards (number->string n)) (n-backwards (string-reverse n-forwards))) (string=? n-forwards n-backwards))) (define (reverse-num n) (string->number (string-reverse (number->string n)))) (define (palindromify p) (define (palin-iter step curr-num) (if (is-palindrome? curr-num) (make-palindromic step curr-num) (palin-iter (+ 1 step) (+ curr-num (reverse-num curr-num))))) (palin-iter 0 p)) ; Main program (for-each (lambda (line) (let* ((n (string->number line)) (result (palindromify n))) (format #t "~A gets palindromic after ~A steps: ~A~%" n (palindromic-steps result) (palindromic-palindrome result)))) (read-lines))