Teaching and learning resources • Re: Advent of Code 2024

Code:

;;; Advent of code 2024 - day3, part1 & 2, on BPI-F3 RISC-V;;; Chez code (load "../../utils.so")(define (string-parse s)  (let ((len (string-length s)))    (cond     ((number? (string->number s))      (let ((n (string->number s)))(if (exact? n) n "")))     ((>= len 3)      (let ((ns (list->string (drop (- len 3) (string->list s)))))(if (string=? ns "mul") "mul" "")))     ((= (string-length s) 1) s)     (else ""))))(define (list-add l)  (cond   ;;((or (null? l) (null? (cdr l)) (null? (cddr l))) 0)   ((< (length l) 6) 0)   ((and (equal? (car l) "mul") (string=? (second l) "(") (number? (third l)) (string=? (fourth l) ",") (number? (fifth l)) (string=? (sixth l) ")"))    (+ (* (third l) (fifth l))       (list-add (drop 6 l))))   (else (list-add (cdr l)))))(define (parse-donts chl)  (letrec ((parse    (lambda (dos n cl)      (cond       ((< n 8) (if dos cl '()))       ((and (char=? (car cl) #\d) dos)(let-values ([(a b) (take-drop 7 cl)])  (if (string=? (list->string a) "don't()")      (parse #f (- n 7) b)      (cons (car cl)    (parse #t (sub1 n) (cdr cl))))))       ((and (char=? (car cl) #\d) (not dos))(let-values ([(a b) (take-drop 4 cl)])  (if (string=? (list->string a) "do()")      (parse #t (- n 4) b)      (parse #f (sub1 n) (cdr cl)))))       (dos (cons (car cl) (parse #t (sub1 n) (cdr cl))))       (else(parse #f (sub1 n) (cdr cl)))))))    (parse #t (length chl) chl)))(define (day3 file)  (let* ((raw (read-lines file)) (charl (string->list (apply string-append raw))) (doss (list->string (parse-donts charl))) (ls1 (map (lambda (s) (string-split-parse s '(#\( #\) #\,))) raw)) (ls2 (string-split-parse doss '(#\( #\) #\,))) (mul-n1  (map (lambda (l) (map (lambda (s) (string-parse s)) l)) ls1)) (mul-n2 (map string-parse ls2)))    (values (apply + (map list-add mul-n1))    (list-add mul-n2))))