Initial commit

2018/day10/day10.ss

@@ -0,0 +1,51 @@
+(import :gerbil/gambit/ports)
+(import :std/pregexp)
+(import :std/srfi/1)
+(import :std/srfi/13)
+(import :std/iter)
+
+(export main)
+
+(defstruct point (x y vx vy))
+
+(def (step-point p n)
+  (make-point (+ (* n (point-vx p)) (point-x p))
+	      (+ (* n (point-vy p)) (point-y p))
+	      (point-vx p)
+	      (point-vy p)))
+
+(def (step-points points n)
+  (map (lambda (p) (step-point p n)) points))
+
+(def (bounding-box points)
+  (let ((xs (map point-x points))
+	(ys (map point-y points)))
+    [(- (apply max xs) (apply min xs) -1)
+     (- (apply max ys) (apply min ys) -1)]))
+
+(def (plot-points points)
+  (def box (bounding-box points))
+  (def min-x (apply min (map point-x points)))
+  (def min-y (apply min (map point-y points)))
+  (def new-points
+    (delete-duplicates
+     (map (lambda (p) [(- (point-x p) min-x) (- (point-y p) min-y)]) points)))
+  (def plot (make-vector (cadr box) #f))
+  (for ((i (in-range (cadr box)))) (vector-set! plot i (make-string (car box) #\.)))
+  (for ((p new-points))
+    (string-set! (vector-ref plot (cadr p)) (car p) #\#))
+  (for ((i (in-range (cadr box))))
+    (displayln (vector-ref plot i))))
+
+(def (main (n "10240") . args)
+  (def params
+    (map (lambda (s) (filter-map string->number (pregexp-split "[<>, ]" s)))
+	 (call-with-input-file "input.txt" (lambda (p) (read-all p read-line)))))
+  (def points (map (lambda (p) (apply make-point p)) params))
+  ;; (def sizes (for/collect ((i (in-range 20000)))
+  ;; 	       [i (apply * (bounding-box (step-points points i)))]))
+  ;; (displayln
+  ;;  (foldl (lambda (s acc) (if (< (cadr s) (cadr acc)) s acc))
+  ;; 	  (car sizes)
+  ;; 	  (cdr sizes)))
+  (plot-points (step-points points (string->number n))))