1 files changed, 26 insertions, 17 deletions

diff --git a/src/2015.02.01-first-attempt.lisp b/src/2015.02.01-first-attempt.lisp
index 14b3cfe..5a71a2b 100644
--- a/src/2015.02.01-first-attempt.lisp
+++ b/src/2015.02.01-first-attempt.lisp
@@ -36,7 +36,7 @@
 
 (defconstant +PUZZLE-INPUT-LIST+
   (loop for sublist in +PUZZLE-INPUT-STRING-LIST+
-        collect (mapcar #'parse-integer sublist))
+        collect (sort (mapcar #'parse-integer sublist) #'>))
   "A list of presents and their numerical dimensions.
 Represented as a list of sublists, with each sublist containing the 3
 dimensions of a particular present.")
@@ -72,30 +72,39 @@ dimensions of a particular present.")
 ;; feet of wrapping paper should they order?
 ;; ---------------------------------------------------------------------
 
+(defun wrapping-paper-base (DIMENSIONS)
+  "Calculate the base amount of wrapping paper needed for a present with `DIMENSIONS'.
+`DIMENSIONS' is assumed to be a list of 3 elements."
+  (apply #'+ (list (* 2 (first DIMENSIONS) (second DIMENSIONS))
+                   (* 2 (first DIMENSIONS) (third DIMENSIONS))
+                   (* 2 (second DIMENSIONS) (third DIMENSIONS)))))
+
+(assert (= 52 (wrapping-paper-base '(4 3 2))))
+(assert (= 42 (wrapping-paper-base '(10 1 1))))
+
+
+(defun wrapping-paper-extra (DIMENSIONS)
+  "Calculate the extra amount of wrapping paper needed for a present with `DIMENSIONS'.
+`DIMENSIONS' is assumed to be a list of 3 elements sorted highest to lowest."
+  (apply #'* (cdr DIMENSIONS)))
 
-(defun smallest-two (DIMENSIONS)
-  "Return the smallest 2 `DIMENSIONS', assuming there are 3."
-  (cdr (sort DIMENSIONS #'>)))
 
 (defun wrapping-paper-area (DIMENSIONS)
-  "Calculate the amount of paper needed for a present with `DIMENSIONS'.
-`DIMENSIONS' is assumed to be a list with 3 elements representing the
-length, width, and height of a particular present."
-  (+ (apply #'+ (list (* 2 (first DIMENSIONS) (second DIMENSIONS))
-                      (* 2 (first DIMENSIONS) (third DIMENSIONS))
-                      (* 2 (second DIMENSIONS) (third DIMENSIONS))))
-     (apply #'* (smallest-two DIMENSIONS))))
-
-;; Test single-present examples from problem text
-(assert (= 58 (wrapping-paper-area '(2 3 4))))
-(assert (= 43 (wrapping-paper-area '(1 1 10))))
+  "Calculate the total amount of paper needed for a present with `DIMENSIONS'.
+`DIMENSIONS' is assumed to be a list of 3 elements."
+  (+ (wrapping-paper-base DIMENSIONS)
+     (wrapping-paper-extra DIMENSIONS)))
+
+(assert (= 58 (wrapping-paper-area '(4 3 2))))
+(assert (= 43 (wrapping-paper-area '(10 1 1))))
+
 
 (defun wrapping-paper-total (PRESENTS)
   "Calculate the total amount of wrapping paper needed for the entire list of `PRESENTS'.
-`PRESENTS' is assumed to be a list of sublists of 3
-elements each, representing the dimensions of each present."
+`PRESENTS' is assumed to be a list of sublists of 3 elements each."
   (apply #'+ (mapcar #'wrapping-paper-area PRESENTS)))
 
+
 ;; Test correct answer
 (assert (= 1586300 (wrapping-paper-total +PUZZLE-INPUT-LIST+)))