【今日湯底】

Given a string made up of letters a, b, and/or c, switch the position of letters a and b (change a to b and vice versa). Leave any incidence of c untouched.

Example:

'acb' --> 'bca'
'aabacbaa' --> 'bbabcabb'

（必須通過以下測試）

(ns kata.test
  (:require [clojure.test :refer :all]
            [kata         :refer [switcheroo]]))

(deftest basic-tests
  (is (= (switcheroo "abc") "bac"))
  (is (= (switcheroo "aaabcccbaaa") "bbbacccabbb"))
  (is (= (switcheroo "ccccc") "ccccc"))
  (is (= (switcheroo "abababababababab")  "babababababababa"))
  (is (= (switcheroo "aaaaa") "bbbbb")))

【我的答案】

(ns kata)
(defn switcheroo [xs]
  (->
    (.replaceAll xs "a" "d")
    (.replaceAll "b" "a")
    (.replaceAll "d" "b"))
  )

思路：

1. 拿目前用過的 java replace 來處理

【其他人的答案】

(ns kata)
(defn switcheroo [xs]
  (clojure.string/replace xs #"a|b" {"a" "b" "b" "a"})
  )

(ns kata)

(defn- switch [c]
  (cond
    (= \a c) \b
    (= \b c) \a
    :else c))

(defn switcheroo [xs]
  (->> (seq xs)
       (map switch)
       (apply str))
  )