advent-of-code/2023/src/day13.clj
2023-12-15 15:29:56 -05:00

121 lines
3.5 KiB
Clojure

(ns day13
(:require
[clojure.string :refer [split-lines]]
[core :refer [get-puzzle-input]]))
(def input (->> (get-puzzle-input 13)
(partition-by empty?)
(filter (comp not-empty first))))
(def sample-input (->> (split-lines "#.##..##.
..#.##.#.
##......#
##......#
..#.##.#.
..##..##.
#.#.##.#.
#...##..#
#....#..#
..##..###
#####.##.
#####.##.
..##..###
#....#..#")
(partition-by empty?)
(filter (comp not-empty first))))
(defn get-col [m c] (->> m
(filter (fn [[[_ col]]]
(= c col)))
(map second)))
(defn get-row [m r] (->> m
(filter (fn [[[row]]] (= r row)))
(map second)))
(defn get-refl-value [m num-rows num-cols]
(let [rows (range 0 num-rows)
cols (range 0 num-cols)]
(apply
concat
(filter
not-empty
(list (->>
rows
(map #(for [r (range (min (inc %) (- (dec num-rows) %)))]
[(- % r) (inc (+ % r))]))
(filter not-empty)
(map (partial map (fn [[a b]]
(= (get-row m a)
(get-row m b)))))
(map-indexed vector)
(filter (comp (partial every? identity)
second))
(filter second)
(map #(vector (inc (first %)) :row)))
(->> cols
(map #(for [c (range (min (inc %) (- (dec num-cols) %)))]
[(- % c) (inc (+ % c))]))
(filter not-empty)
(map (partial map (fn [[a b]]
(= (get-col m a)
(get-col m b)))))
(map-indexed vector)
(filter (comp (partial every? identity)
second))
(filter second)
(map #(vector (inc (first %)) :col))))))))
(defn gen-map [input]
(->> input
(map-indexed (fn [row line]
(map-indexed (fn [col c] [[row col] c])
line)))
(apply concat)
(into (sorted-map))))
;; part 1
(->> input
(map #(get-refl-value (gen-map %)
(count %)
(count (first %))))
(map first)
(map #(update % 1 (fn [x] (condp = x
:col 1
:row 100))))
(map (partial apply *))
(reduce +)
)
(defn print-board [m num-rows num-cols]
(println)
(doseq [row (range num-rows)]
(doseq [col (range num-cols)]
(print (m [row col])))
(println)))
;; part 2
(->> input
(mapv
#(let [num-rows (count %)
num-cols (count (first %))
m (gen-map %)
smudge (first (get-refl-value m num-rows num-cols))]
(->> (for [r (range num-rows)
c (range num-cols)]
(->> (get-refl-value
(update m [r c] (fn [c] (if (= c \#) \. \#)))
num-rows
num-cols)
(filter (partial not= smudge))))
(filter not-empty)
(apply concat))))
(map first)
(map #(update % 1 (fn [x] (condp = x
:col 1
:row 100))))
(map (partial apply *))
(reduce +))