From 543f988df5e6a221a3c990eec574dd7085debd40 Mon Sep 17 00:00:00 2001
From: Tyler Wardhaugh <tyler.wardhaugh@gmail.com>
Date: Fri, 19 Nov 2021 22:25:31 -0800
Subject: Ch139 (Clojure): Task 2

---
 challenge-139/tyler-wardhaugh/clojure/deps.edn     |  3 ++-
 .../clojure/src/tw/weekly/c139/t2.clj              | 29 ++++++++++++++++++++--
 .../clojure/test/tw/weekly/c139/t2_test.clj        |  6 ++++-
 3 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/challenge-139/tyler-wardhaugh/clojure/deps.edn b/challenge-139/tyler-wardhaugh/clojure/deps.edn
index 5b1400b27e..3386938e59 100644
--- a/challenge-139/tyler-wardhaugh/clojure/deps.edn
+++ b/challenge-139/tyler-wardhaugh/clojure/deps.edn
@@ -1,5 +1,6 @@
 {:paths ["src" "resources"]
- :deps {org.clojure/clojure {:mvn/version "1.10.3"}}
+ :deps {org.clojure/clojure {:mvn/version "1.10.3"}
+        com.hypirion/primes {:mvn/version "0.2.2"}}
  :aliases
  {:test {:extra-paths ["test"]
          :extra-deps {org.clojure/test.check {:mvn/version "1.1.0"}
diff --git a/challenge-139/tyler-wardhaugh/clojure/src/tw/weekly/c139/t2.clj b/challenge-139/tyler-wardhaugh/clojure/src/tw/weekly/c139/t2.clj
index cb59f2c64e..737d6ea02b 100644
--- a/challenge-139/tyler-wardhaugh/clojure/src/tw/weekly/c139/t2.clj
+++ b/challenge-139/tyler-wardhaugh/clojure/src/tw/weekly/c139/t2.clj
@@ -1,10 +1,35 @@
 (ns tw.weekly.c139.t2
-  (:require [clojure.edn :as edn]))
+  (:require [com.hypirion.primes :as p]))
 
 ;;;
 ; Task description for TASK #2 › Long Primes
 ;;;
+(def BASE 10)
+
+(defn cyclic?
+  [n]
+  (let [s (str n)
+        len (count s)
+        ndigits (set s)
+        ndigits' (conj ndigits \0)
+        f (fn [x] (let [odigits (-> x str set)]
+                    (or (= ndigits odigits) (= ndigits' odigits))))]
+    (every? f (map #(* n %) (range 2 len)))))
+
+(defn long-prime?
+  [n]
+  (-> (biginteger BASE)
+      (.pow (dec n))
+      (.subtract (biginteger 1))
+      (.divide (biginteger n))
+      cyclic?))
+
+(defn long-primes
+  []
+  (let [xf (comp (drop 2) (filter long-prime?) (take 5))]
+    (sequence xf (p/primes))))
 
 (defn -main
   "Run Task 2."
-  [& _])
+  [& _]
+  (long-primes))
diff --git a/challenge-139/tyler-wardhaugh/clojure/test/tw/weekly/c139/t2_test.clj b/challenge-139/tyler-wardhaugh/clojure/test/tw/weekly/c139/t2_test.clj
index 02cd77de88..b05222cb04 100644
--- a/challenge-139/tyler-wardhaugh/clojure/test/tw/weekly/c139/t2_test.clj
+++ b/challenge-139/tyler-wardhaugh/clojure/test/tw/weekly/c139/t2_test.clj
@@ -1,3 +1,7 @@
 (ns tw.weekly.c139.t2-test
   (:require [clojure.test :refer [deftest is testing]]
-            [tw.weekly.c139.t2 :refer []]))
+            [tw.weekly.c139.t2 :refer [long-primes]]))
+
+(deftest examples
+  (testing "Examples from description"
+    (is (= [7 17 19 23 29] (long-primes)))))
-- 
cgit