Implement Clojure solutions and tests for chapter 1, question 1

clojure/chapter01/01_01.clj

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+; Clojure solution to question 1.1 from Cracking the Coding Interview, 5th Edition.
+; Nitin Punjabi
+; github.com/nitinpunjabi
+; [email protected]
+(ns chapter01.01-01
+  (:require [clojure.test :as t]))
+
+(defn unique-by-set-count?
+  "Solution using a set."
+  [s]
+  (let [coll (into #{} s)]
+    (= (count coll) (count s))))
+
+(defn unique-by-partition?
+  "Solution using partitioning."
+  [s]
+  (let [parts (partition-by identity (sort s))]
+    (not (some #(> (count %) 1) parts))))
+
+(t/deftest unique-by-set-count
+  (t/is (= (unique-by-set-count? "") true))
+  (t/is (= (unique-by-set-count? "a") true))
+  (t/is (= (unique-by-set-count? "ab") true))
+  (t/is (= (unique-by-set-count? "aab") false))
+  (t/is (= (unique-by-set-count? "aba") false)))
+
+(t/deftest unique-by-partition
+  (t/is (= (unique-by-partition? "") true))
+  (t/is (= (unique-by-partition? "a") true))
+  (t/is (= (unique-by-partition? "ab") true))
+  (t/is (= (unique-by-partition? "aab") false))
+  (t/is (= (unique-by-partition? "aba") false)))