Run-length encoding: Difference between revisions
Content added Content deleted
(adding scheme) |
|||
| Line 2,567: | Line 2,567: | ||
(define (run-length-encode s) |
(define (run-length-encode s) |
||
(let ((n (string-length s))) |
(let ((n (string-length s))) |
||
(let loop (( |
(let loop ((i (- n 2)) (c (string-ref s (- n 1))) (k 1) (v '())) |
||
(if (negative? |
(if (negative? i) (cons (cons k c) v) |
||
(let ((x (string-ref s |
(let ((x (string-ref s i))) |
||
(if (char=? c x) (loop (- |
(if (char=? c x) (loop (- i 1) c (+ k 1) v) |
||
(loop (- |
(loop (- i 1) x 1 (cons (cons k c) v)))))))) |
||
(run-length-encode "WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW") |
(run-length-encode "WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW") |
||
; ((12 . #\W) (1 . #\B) (12 . #\W) (3 . #\B) (24 . #\W) (1 . #\B) (14 . #\W)) |
; ((12 . #\W) (1 . #\B) (12 . #\W) (3 . #\B) (24 . #\W) (1 . #\B) (14 . #\W)) |
||
(run-length-decode '((12 . #\W) (1 . #\B) (12 . #\W) (3 . #\B) (24 . #\W) (1 . #\B) (14 . #\W))) |
(run-length-decode '((12 . #\W) (1 . #\B) (12 . #\W) (3 . #\B) (24 . #\W) (1 . #\B) (14 . #\W))) |
||
; "WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW"</ |
; "WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW"</lang> |
||
=={{header|sed}}== |
=={{header|sed}}== |
||