Fixed Day 13

Welp sort is destructive - now I know. Also very minor changes to day14.lisp
abraemer · Dec 14, 2018 · c111204 · c111204
1 parent 668ae72
commit c111204
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Showing 2 changed files with 31 additions and 54 deletions.
diff --git a/day13.lisp b/day13.lisp
@@ -62,73 +62,50 @@
         (#\+ (day13-turn cart)))
       cart)))
 
-(defun day13-check-collision! (cart carts)
+(defun day13-check-collision! (cart minecarts)
   (let ((collisions
           (remove-if #'minecart-crashed
-                     (remove (minecart-pos cart) carts :key #'minecart-pos :test (complement #'=)))))
-    (unless (<= 1 (length collisions))
-      (format t "Collisions: ~%~{~S~%~}~%" collisions)
+                     (remove (minecart-pos cart) minecarts :key #'minecart-pos :test (complement #'=)))))
+    (unless (= 1 (length collisions))
       (mapc (lambda (c) (setf (minecart-crashed c) t)) collisions))))
 
 (defun day13-step! (board minecarts)
   (loop
-    :for minecart :in (sort minecarts #'< :key #'minecart-pos)
+    :for minecart :in (sort (copy-list minecarts) #'< :key #'minecart-pos)
     :unless (minecart-crashed minecart)
     :do (day13-move-cart! board minecart)
-    :and :do (day13-check-collision! minecart (remove-if #'minecart-crashed minecarts))))
-
-(defun day13-print-state (board minecarts)
-  (let* ((width (array-dimension board 1))
-         (copy (make-array (array-dimensions board)
-                           :displaced-to (copy-seq
-                                          (make-array (array-total-size board) :displaced-to board)))))
-    (loop :for cart :in minecarts
-          :do (setf (row-major-aref copy (minecart-pos cart)) (minecart-direction cart))
-          :finally
-          (format t "~{~a~%~}~%"
-                  (loop :for y :below (array-dimension board 0)
-                        :collect (coerce (make-array width :displaced-to copy :displaced-index-offset (* y width))
-                                         'string))))))
+    :and :do (day13-check-collision! minecart minecarts)))
 
 (defun day13-pos->coord (board pos)
   (multiple-value-bind (y x) (floor pos (array-dimension board 1))
     (list x y)))
 
 (defun day13 ()
   (destructuring-bind (board carts) (day13-parse-input)
-    (format t "The first crash occurs at (~{~a~^,~}).~%"
-            (loop
-              :until (some #'minecart-crashed carts)
-              :do (day13-step! board carts)
-              :finally (return (day13-pos->coord
-                                board
-                                (minecart-pos (find-if #'minecart-crashed carts))))))
+    (loop
+      :until (some #'minecart-crashed carts)
+      :do (day13-step! board carts)
+      :finally
+      (format t "The first crash occurs at (~{~a~^,~}).~%"
+              (day13-pos->coord board (minecart-pos (find-if #'minecart-crashed carts)))))
     (loop
       :for uncrashed := (remove-if #'minecart-crashed carts)
       :until (= 1 (length uncrashed))
       :do (day13-step! board uncrashed)
       :finally
-      (progn
-        (format t "After the last crash the last minecart is at (~{~a~^,~}).~%"
-                (day13-pos->coord board (minecart-pos (first uncrashed))))
-        (format t "~S~%~%" (first uncrashed))))
-    carts))
-
-(defparameter test-inp
-  (split-seq
-   "/->-\\        
-|   |  /----\\
-| /-+--+-\\  |
-| | |  | v  |
-\\-+-/  \\-+--/
-  \\------/   " #\Newline))
+      (format t "After the last crash the last minecart is at (~{~a~^,~}).~%"
+                (day13-pos->coord board (minecart-pos (first uncrashed)))))))
 
-(defparameter test-inp2
-  (split-seq
-   "/>-<\\  
-|   |  
-| /<+-\\
-| | | v
-\\>+</ |
-  |   ^
-  \\<->/" #\Newline))
+;;helper - bit ugly
+(defun day13-print-state (board minecarts)
+  (let* ((width (array-dimension board 1))
+         (copy (make-array (array-dimensions board)
+                           :displaced-to (copy-seq
+                                          (make-array (array-total-size board) :displaced-to board)))))
+    (loop :for cart :in minecarts
+          :do (setf (row-major-aref copy (minecart-pos cart)) (minecart-direction cart))
+          :finally
+          (format t "~{~a~%~}~%"
+                  (loop :for y :below (array-dimension board 0)
+                        :collect (coerce (make-array width :displaced-to copy :displaced-index-offset (* y width))
+                                         'string))))))
diff --git a/day14.lisp b/day14.lisp
@@ -16,7 +16,7 @@
               :for (rest digit) := (multiple-value-list (floor number 10))
               :then (multiple-value-list (floor rest 10))
               :collect digit
-              :while (> rest 0))))
+              :while (> rest 0)))))
 
 (defun day14 (&optional (input 327901))
   (loop :with recipes := (day14-prepare-recipes input)
@@ -33,16 +33,16 @@
 (defun day14-extra (&optional (input 327901))
   (loop :with recipes := (day14-prepare-recipes 21000000)
         :with code := (day14-digits input)
-        :with at := 0
-        :for elf1 := 0 :then (mod (+ elf1 1 recipe1) (length recipes))
-        :for elf2 := 1 :then (mod (+ elf2 1 recipe2) (length recipes))
+        :with at fixnum := 0
+        :for elf1 fixnum := 0 :then (mod (+ elf1 1 recipe1) (length recipes))
+        :for elf2 fixnum := 1 :then (mod (+ elf2 1 recipe2) (length recipes))
         :for recipe1 := (aref recipes elf1)
         :for recipe2 := (aref recipes elf2)
         :do (dolist (new-recipe (day14-digits (+ recipe1 recipe2)))
               (vector-push-extend new-recipe recipes 10000)
               (cond
                 ((null (nth at code)) (incf at))
-                ((eql (nth at code) new-recipe) (incf at))
+                ((= (nth at code) new-recipe) (incf at))
                 (t (setf at 0))))
         :while (nth at code)
         :finally (format t "Answer Part2: ~a~%"