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@@ -16,12 +16,12 @@
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(define (find-start)
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(let loop ((x 0) (y 0))
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(if (>= y height)
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- #f
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- (if (>= x width)
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- (loop 0 (+ y 1))
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- (if (char=? #\S (char-at x y))
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- (cons x y)
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- (loop (+ x 1) y))))))
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+ #f
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+ (if (>= x width)
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+ (loop 0 (+ y 1))
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+ (if (char=? #\S (char-at x y))
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+ (cons x y)
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+ (loop (+ x 1) y))))))
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(define start (find-start))
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@@ -37,18 +37,18 @@
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(define down (cons (car start) (+ (cdr start) 1)))
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(define left (cons (- (car start) 1) (cdr start)))
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(define right (cons (+ (car start) 1) (cdr start)))
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- (cond ((and (valid-pos? up)
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- (member (char-at (car up) (cdr up)) (list #\| #\F #\7)))
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- up)
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- ((and (valid-pos? down)
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- (member (char-at (car down) (cdr down)) (list #\| #\L #\J )))
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- down)
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- ((and (valid-pos? left)
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- (member (char-at (car left) (cdr left)) (list #\- #\F #\L )))
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- left)
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- ((and (valid-pos? right)
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- (member (char-at (car right) (cdr right)) (list #\- #\7 #\J)))
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- right))))
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+ (cond ((and (valid-pos? up)
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+ (member (char-at (car up) (cdr up)) (list #\| #\F #\7)))
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+ up)
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+ ((and (valid-pos? down)
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+ (member (char-at (car down) (cdr down)) (list #\| #\L #\J )))
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+ down)
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+ ((and (valid-pos? left)
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+ (member (char-at (car left) (cdr left)) (list #\- #\F #\L )))
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+ left)
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+ ((and (valid-pos? right)
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+ (member (char-at (car right) (cdr right)) (list #\- #\7 #\J)))
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+ right))))
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(define (next cur recent)
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(define up (cons (car cur) (- (cdr cur) 1)))
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@@ -65,8 +65,8 @@
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((char=? c #\J) (list up left))))
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(let loop ((cur possible-pos))
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(if (not (equal? (car cur) recent))
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- (car cur)
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- (loop (cdr cur)))))
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+ (car cur)
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+ (loop (cdr cur)))))
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(define pipes (make-hash))
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@@ -74,22 +74,22 @@
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(let loop ((i 0) (cur first-pos) (recent start))
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(hash-set! pipes cur '())
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(if (equal? cur start)
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- i
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- (let ()
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- (define next-loc (next cur recent))
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- (loop (+ i 1) next-loc cur)))))
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+ i
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+ (let ()
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+ (define next-loc (next cur recent))
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+ (loop (+ i 1) next-loc cur)))))
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(define (mark-junk)
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(let loop ((x 0) (y 0))
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(if (>= y height)
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- (void)
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- (if (>= x width)
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- (loop 0 (+ y 1))
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- (let ()
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- (when (and (not (hash-has-key? pipes (cons x y)))
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- (not (char=? #\. (char-at x y))))
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- (string-set! (vector-ref diagram y) x #\.))
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- (loop (+ 1 x) y))))))
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+ (void)
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+ (if (>= x width)
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+ (loop 0 (+ y 1))
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+ (let ()
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+ (when (and (not (hash-has-key? pipes (cons x y)))
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+ (not (char=? #\. (char-at x y))))
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+ (string-set! (vector-ref diagram y) x #\.))
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+ (loop (+ 1 x) y))))))
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(let ()
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(simulate)
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@@ -99,14 +99,14 @@
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(define (ray-cast-find s)
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(let loop ((i 0) (flag #f) (ret 0))
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(if (>= i width)
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- ret
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- (let ()
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- (define char (string-ref s i))
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- (if (and flag (char=? char #\.))
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- (loop (+ 1 i) flag (+ 1 ret))
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- (if (member char (list #\| #\F #\7))
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- (loop (+ 1 i) (not flag) ret)
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- (loop (+ 1 i) flag ret)))))))
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+ ret
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+ (let ()
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+ (define char (string-ref s i))
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+ (if (and flag (char=? char #\.))
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+ (loop (+ 1 i) flag (+ 1 ret))
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+ (if (member char (list #\| #\F #\7))
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+ (loop (+ 1 i) (not flag) ret)
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+ (loop (+ 1 i) flag ret)))))))
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(apply + (map ray-cast-find (vector->list diagram)))
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