Calculate the number of chars to remove to make two strings anagrams of each other.

anagram-difference.clj

(ns anagram-difference)

(defn add-to-bag [bag item]
  (update bag item (fnil inc 0)))

(defn sub-from-bag [bag item]
  (update bag item (fnil dec 0)))

(defn anagram-difference [w1 w2]
  "Example
   First word : c od e w ar s (4 letters removed)
   Second word : ha c k er r a nk (6 letters removed)
   Result : 10"
  (-> {}
      (#(reduce add-to-bag % w1))
      (#(reduce sub-from-bag % w2))
      ((fn [bag] (apply + (map #(Math/abs %) (vals bag)))))))