Discussion on: Daily Challenge #208 - Delete Occurrences of an Element

(defn delete-nth [xs n]
  (-> (reduce (fn [[cnts xs'] x]
                [(update cnts x (fnil inc 0))
                 (cond-> xs' (< (cnts x 0) n) (conj x))])
              [{} []] xs)
      (second)))

(defn delete-nth' [xs n]
  (loop [cnts {}, xs' [], [x & rst] xs]
    (if x
      (recur (update cnts x (fnil inc 0))
             (cond-> xs' (< (cnts x 0) n) (conj x))
             rst)
      xs')))