drop-starts-same.clj

;;;; http://npnl.hatenablog.jp/entry/20110812/1313138407

(ns twenty-five-minutes-programming.drop-starts-same
  (:use [clojure.test :only [are]]))


(defn drop-starts-same
  [& args]
  (if (some empty? args)
    args
    (let [drop-count
          (->> args
            (apply map vector)
            (take-while (partial apply =))
            count)]
      (->> args
        (map (partial drop drop-count))
        (map (partial apply str))))))


(are [args expected]
  (= (apply drop-starts-same args) expected)
  ["abcdef" "abc123"] ["def" "123"]
  ["あいうえお" "あいさんさん" "あいどる"] ["うえお" "さんさん" "どる"]
  ["12345" "67890" "12abc"] ["12345" "67890" "12abc"]
  ["a" "ab" "abc"] ["" "b" "bc"]
  [nil "a" "ab"] [nil "a" "ab"]
  ["" "a" "ab"] ["" "a" "ab"]
  )