jamesoly

;; joly's solution to Levenshtein Distance
;; https://4clojure.com/problem/101

;; Slow, but finishes fast enough for test problems.
;; None of the self-memoized versions worked without
;; using def, but memoizing this version gave a
;; speedup from 2500 msec -> 10 msec.

(fn lev [s t]
    (cond

jamesoly

(let [mem (atom {})]
  (fn lev [s t]
    (cond
    (empty? s) (count t)
    (empty? t) (count s)
    :else (if-let [e (find @mem [s t])]
            (val e)
            (let [ns (rest s)
                  nt (rest t)
                  ret (if (= (first s) (first t))