advent-of-code-2023-day8.clj

advent-of-code-2023-day8-cleaner.clj

(defn path-follower [[dir & rest-dirs] graph edge]
  (let [next-edge ((edge graph) ({:L 0 :R 1} dir))]
    (->> (path-follower rest-dirs graph next-edge)
         (cons edge)
         lazy-seq)))

(defn steps [path graph start-edge goal]
  (->> (path-follower (cycle path) graph start-edge)
       (take-while #(not= % goal))
       count))

advent-of-code-2023-day8.clj

(defn path-follower [path-seq graph edge]
  (let [dir (first path-seq)
        next-edge ((edge graph) ({:L 0 :R 1} dir))]
    (lazy-seq
      (cons position
            (path-follower (drop 1 path-seq) graph next-edge)))))

(defn steps [path graph start-edge goal]
  (count
    (take-while #(not= % goal)
                (path-follower (cycle path) graph start-edge))))