AoC 2019, Day 4

day4.clj

(defn increasing? [d]
  (re-matches #"1*2*3*4*5*6*7*8*9*" d))

(defn repeating-by? [op s]
  (->> (frequencies s)
       (some #(op 2 (val %)))))

(defn solve-day4-p1 [from to]
  (->> (range from (inc to))
       (map str)
       (filter #(and (increasing? %) (repeating-by? <= %)))
       count))

(defn solve-day4-p2 [from to]
  (->> (range from (inc to))
       (map str)
       (filter #(and (increasing? %) (repeating-by? == %)))
       count))

(comment
  (= 1767 (solve-day4-p1 145852 616942))
  (= 1192 (solve-day4-p2 145852 616942)))