commit c93ed9ea685379d2ab77e1b8bad976783d961dda parent b8b20282833063ad94b1908cc8306e85aedf677e Author: Lukas Henkel <lh@entf.net> Date: Wed, 13 Dec 2023 07:05:30 +0100 Day 13 task 2 Diffstat:
| M | src/day-13.lisp | | | 37 | +++++++++++++++++++++++++------------ |
| M | t/day-13.lisp | | | 3 | ++- |
2 files changed, 27 insertions(+), 13 deletions(-)
diff --git a/src/day-13.lisp b/src/day-13.lisp @@ -19,21 +19,34 @@ (defun find-point-of-reflection (map type) (multiple-value-bind (primary-axis-length secondary-axis-length make-point) (reflection-finding-properties map type) - (loop for reflection-point from 0 below (1- primary-axis-length) + (loop with perfect-point-of-reflection = nil + with imperfect-point-of-reflection = nil + for reflection-point from 0 below (1- primary-axis-length) for reflection-length = (min (1+ reflection-point) (- primary-axis-length reflection-point 1)) - when (loop repeat reflection-length - for compare-1 downfrom reflection-point - for compare-2 from (1+ reflection-point) - always (loop for secondary-axis-point from 0 below secondary-axis-length - for point-1 = (funcall make-point compare-1 secondary-axis-point) - for point-2 = (funcall make-point compare-2 secondary-axis-point) - always (char= (map-cell map point-1) - (map-cell map point-2)))) - do (return (1+ reflection-point))))) + for reflection-imperfections = (loop repeat reflection-length + for compare-1 downfrom reflection-point + for compare-2 from (1+ reflection-point) + for reflection-matches = (loop for secondary-axis-point from 0 below secondary-axis-length + for point-1 = (funcall make-point compare-1 secondary-axis-point) + for point-2 = (funcall make-point compare-2 secondary-axis-point) + when (char= (map-cell map point-1) + (map-cell map point-2)) + sum 1) + sum (- secondary-axis-length reflection-matches)) + when (= reflection-imperfections 0) + do (setf perfect-point-of-reflection (1+ reflection-point)) + when (= reflection-imperfections 1) + do (setf imperfect-point-of-reflection (1+ reflection-point)) + finally (return (list perfect-point-of-reflection imperfect-point-of-reflection))))) (defun day-13 (input) (loop for map = (make-map input) while map - sum (or (find-point-of-reflection map :vertical) - (* (find-point-of-reflection map :horizontal) 100)))) + for (perfect-vertical-reflection imperfect-vertical-reflection) = (find-point-of-reflection map :vertical) + for (perfect-horizontal-reflection imperfect-horizontal-reflection) = (find-point-of-reflection map :horizontal) + sum (or perfect-vertical-reflection + (* perfect-horizontal-reflection 100)) into task-1 + sum (or imperfect-vertical-reflection + (* imperfect-horizontal-reflection 100)) into task-2 + finally (return (values task-1 task-2)))) diff --git a/t/day-13.lisp b/t/day-13.lisp @@ -20,4 +20,5 @@ #####.##. ..##..### #....#..#") - (assert= 405 task-1))) + (assert= 405 task-1) + (assert= 400 task-2)))