Add q56

src/ex/q056.clj

@@ -0,0 +1,9 @@
+;; https://4clojure.oxal.org/#/problem/056
+
+(ns ex.q056)
+
+(defn ans
+  "Problem 56, Find Distinct Items. restrictions: distinct"
+  [coll]
+  (let [seen (atom #{})]
+    (into [] (filter #(if (contains? @seen %) false (do (swap! seen conj %) true)) coll))))

test/ex/q056_test.clj

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+;; https://4clojure.oxal.org/#/problem/056
+
+(ns ex.q056-test
+  (:require [clojure.test :as t]
+            [ex.q056 :as sut]))
+
+(t/deftest test-q56
+  (t/testing "Problem 56, Find Distinct Items"
+    (t/is (= [1 2 3 4] (sut/ans [1 2 1 3 1 2 4])))
+    (t/is (= [:a :b :c] (sut/ans [:a :a :b :b :c :c])))
+    (t/is (= '([2 4] [1 2] [1 3]) (sut/ans '([2 4] [1 2] [1 3] [1 3]))))
+    (t/is (= (range 50) (sut/ans (range 50))))))