commit 5a0f4f798db2175b88afe1898e967e440821ebe7 parent 64b7929c1294e58683258bb94937834b0bc097bb Author: mpizzzle <m@michaelpercival.xyz> Date: Thu, 3 Dec 2020 19:23:19 +0000 cutting down utility functions Diffstat:
| M | 2020/puzzle_2.scm | | | 47 | +++++++++++++++++++---------------------------- |
1 file changed, 19 insertions(+), 28 deletions(-)
diff --git a/2020/puzzle_2.scm b/2020/puzzle_2.scm @@ -1,36 +1,27 @@ -(define (string-index str chr idx) - (if (not (null? str)) - (if (char=? (car (string->list str)) chr) - idx - (string-index (list->string (cdr (string->list str))) chr (+ idx 1))) - -1)) +(define (string-idx str chr) + (- (length (string->list str)) (length (memq chr (string->list str))))) -(define (valid-password entry policy) - (let - ((idx (string-index entry #- 0)) - (idx2 (string-index entry #space 0))) - (let - ((i (string->number (substring entry 0 idx))) - (j (string->number (substring entry (+ idx 1) idx2))) - (c (string-ref entry (+ idx2 1))) - (s (substring entry (+ idx2 4) (string-length entry)))) - (policy s c i j)))) +(define (char-count str chr) + (apply + (map (lambda (b) (if b 1 0))(map (lambda (c) (char=? c chr)) (string->list str))))) -(define (loop entries policy) +(define (validate-passwords entries policy) (if (not (null? entries)) - (+ (valid-password (car entries) policy) - (loop (cdr entries) policy)) + (+ (let + ((idx (string-idx (car entries) #-)) + (idx2 (string-idx (car entries) #space)) + (entry (car entries))) + (let + ((i (string->number (substring entry 0 idx))) + (j (string->number (substring entry (+ idx 1) idx2))) + (c (string-ref entry (+ idx2 1))) + (s (substring entry (+ idx2 4) (string-length entry)))) + (policy s c i j))) + (validate-passwords (cdr entries) policy)) 0)) -(define (char-count str chr count) - (if (not (= 0 (string-length str))) - (char-count (list->string (cdr (string->list str))) chr - (if (char=? (car (string->list str)) chr)(+ count 1) count)) - count)) - (define policy-1 (lambda (s c i j) - (let ((count (char-count s c 0))) + (let ((count (char-count s c))) (if (and (>= count i) (<= count j)) 1 0)))) (define policy-2 @@ -41,5 +32,5 @@ (load "read_lines.scm") (define input (read-lines "files/2.txt" (lambda (x) x))) -(display (loop input policy-1)) (newline) -(display (loop input policy-2)) (newline) +(display (validate-passwords input policy-1)) (newline) +(display (validate-passwords input policy-2)) (newline)