projects / adventofcode2020.git / blame
| Commit | Line | Data |
|---|---|---|
| 75918e33 | 1 | (asdf:load-system :adventofcode2020) |
| 37dc4d4e JK |
2 | (in-package #:adventofcode2020) |
| 3 | ||
| 4 | (defun tree-collisions (slope tree-map) | |
| 5 | (destructuring-bind (rise run) slope | |
| 6 | (loop with terrain-width = (-> tree-map first length) | |
| 7 | for i upfrom 0 by run | |
| 8 | for j upfrom 0 | |
| 9 | for terrain-line in tree-map | |
| 10 | when (->> rise (mod j) (= 0)) | |
| 11 | counting (->> terrain-width | |
| 12 | (mod i) | |
| 13 | (char terrain-line) | |
| 14 | (char= #\#))))) | |
| 15 | ||
| 16 | (day 03 input | |
| 17 | (let ((tree-map (list-from input))) | |
| 18 | (part1 (tree-collisions '(1 3) tree-map)) | |
| 19 | (part2 (->> '((1 1) (1 3) (1 5) (1 7) (2 1)) | |
| 20 | (mapcar (fn* (tree-collisions _ tree-map))) | |
| 21 | (reduce #'*))))) | |
| 22 | ||
| 23 | (def-suite day03) | |
| 24 | (in-suite day03) | |
| 25 | ||
| 26 | (test single-collision-check | |
| 27 | (is (equal | |
| 28 | 7 | |
| 29 | (tree-collisions '(1 3) '("..##......." | |
| 30 | "#...#...#.." | |
| 31 | ".#....#..#." | |
| 32 | "..#.#...#.#" | |
| 33 | ".#...##..#." | |
| 34 | "..#.##....." | |
| 35 | ".#.#.#....#" | |
| 36 | ".#........#" | |
| 37 | "#.##...#..." | |
| 38 | "#...##....#" | |
| 39 | ".#..#...#.#"))))) | |
| 40 | ||
| 41 | ||
| 42 | (test multiple-collision-check | |
| 43 | (is (equal | |
| 44 | '(2 7 3 4 2) | |
| 45 | (mapcar (fn* (tree-collisions _ '("..##......." | |
| 46 | "#...#...#.." | |
| 47 | ".#....#..#." | |
| 48 | "..#.#...#.#" | |
| 49 | ".#...##..#." | |
| 50 | "..#.##....." | |
| 51 | ".#.#.#....#" | |
| 52 | ".#........#" | |
| 53 | "#.##...#..." | |
| 54 | "#...##....#" | |
| 55 | ".#..#...#.#"))) | |
| 56 | '((1 1) (1 3) (1 5) (1 7) (2 1)))))) | |
| 57 | ||
| 58 | (run! 'day03) |