Day 07 - Better part 2 solution

2021-12-07 18:16:20 +01:00 · 2021-12-07 18:16:20 +01:00 · 0cacd9883d
parent 74b937f5df
commit 0cacd9883d
1 changed files with 4 additions and 4 deletions
--- a/07/solution.lisp
+++ b/07/solution.lisp
@ -38,10 +38,10 @@
    (/ (* cost-base (+ cost-base 1)) 2)))

 (defun part2 (data)
-  (let ((lowest (apply #'min data))
-        (highest (apply #'max data)))
-    (loop for x from lowest to highest
-          minimizing (fuel-cost data x #'compounding-cost))))
+  (let* ((sum (reduce #'+ data))
+         (count (length data)))
+    (min (fuel-cost data (floor sum count) #'compounding-cost)
+         (fuel-cost data (ceiling sum count) #'compounding-cost))))

 (format t "===== Part 1 =====")
 (format t "Result: ~A~%~%" (time (part1 *data*)))