fork download
copy 
  1. ; word sets
  2.  
  3. (define (alpha-set cs)
  4.   (let ((s (make-vector 26 #f)))
  5.     (do ((cs cs (cdr cs)))
  6.         ((null? cs) s)
  7.       (let ((t (- (char->integer (car cs)) 97)))
  8.         (vector-set! s t #t)))))
  9.  
  10. (define (word-set s word)
  11.   (let loop ((cs (string->list word)))
  12.     (if (null? cs) #t
  13.       (let ((t (- (char->integer (car cs)) 97)))
  14.         (if (vector-ref s t) (loop (cdr cs)) #f)))))
  15.  
  16. (define s (alpha-set '(#\a #\c #\t)))
  17. (display (word-set s "act")) (newline)
  18. (display (word-set s "tact")) (newline)
  19. (display (word-set s "stop")) (newline)
  20.  
  21. (define (alpha-count cs)
  22.   (let ((c (make-vector 26 0)))
  23.     (do ((cs cs (cdr cs)))
  24.         ((null? cs) c)
  25.       (let ((t (- (char->integer (car cs)) 97)))
  26.         (vector-set! c t (+ (vector-ref c t) 1))))))
  27.  
  28. (define (word-count c word)
  29.   (let ((c (vector-copy c)))
  30.     (let loop ((cs (string->list word)))
  31.       (if (null? cs) #t
  32.         (let ((t (- (char->integer (car cs)) 97)))
  33.           (vector-set! c t (- (vector-ref c t) 1))
  34.           (if (negative? (vector-ref c t)) #f
  35.             (loop (cdr cs))))))))
  36.  
  37. (define c (alpha-count '(#\a #\c #\t)))
  38. (display (word-count c "act")) (newline)
  39. (display (word-count c "tact")) (newline)
  40. (display (word-count c "stop")) (newline)
Success #stdin #stdout 0.01s 42848KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
#t
#t
#f
#t
#f
#f
https://ideone.com/mQoc3j
language:
Scheme (guile 2.2.4)
created:
7 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!