Add q81

Author: davidkun

src/ex/q081.clj

@@ -0,0 +1,11 @@
+;; https://4clojure.oxal.org/#/problem/081
+ 
+(ns ex.q081)
+
+(defn ans
+  "Problem 81, Set Intersection"
+  [a b]
+  (let [union (apply conj a b)]
+    (->> union
+         (filter #(and (contains? a %) (contains? b %)))
+         set)))

test/ex/q081_test.clj

@@ -0,0 +1,11 @@
+;; https://4clojure.oxal.org/#/problem/081
+ 
+(ns ex.q081-test
+  (:require [clojure.test :as t]
+            [ex.q081 :as sut]))
+
+(t/deftest test-q81
+  (t/testing "Problem 81, Set Intersection"
+    (t/is (= #{2 3} (sut/ans #{0 1 2 3} #{2 3 4 5})))
+    (t/is (= #{} (sut/ans #{0 1 2} #{3 4 5})))
+    (t/is (= #{:a :c :d} (sut/ans #{:a :b :c :d} #{:c :e :a :f :d})))))