advent 2017 day 1

advent-day-1-part-2.clj

(defn double-up [coll]
  (->> (repeat coll)
       (take 2)
       (apply concat)))

(defn split-out-by-parts [length coll]
  (->> (partition (inc (/ (count coll) 4)) 1 coll )
       (take length)
       (map (juxt first last))))

(defn every-same-pred [candidate]
  (apply = candidate))

(defn every-same-pred-filter [coll]
  (filter every-same-pred coll))

(defn prepare-coll [str]
  (let [length (if even? (count str) (count str))]
    (->> (mapv #(Integer/parseInt %) (clojure.string/split str #""))
         double-up
         ((partial split-out-by-parts length))
         every-same-pred-filter
         (map first)
         (reduce +))))