transform-n

transform.clj

(defn transform-n
    [n words]
    (->> words
      (partition n 1)
      (reduce (fn [acc [w next-w]]
                (update-in acc
                           [w next-w]
                           (fnil inc 0)))
              {})))

(transform-n 2 ["it" "was" "a" "dark" "and" "stormy" "night"])
(transform-n 4 ["it" "was" "a" "dark" "and" "stormy" "night"])