Ch138 (Clojure): Task 2

3 files changed, 40 insertions, 5 deletions

diff --git a/challenge-138/tyler-wardhaugh/clojure/deps.edn b/challenge-138/tyler-wardhaugh/clojure/deps.edn
index 54edd9d65e..15aa02e4d4 100644
--- a/challenge-138/tyler-wardhaugh/clojure/deps.edn
+++ b/challenge-138/tyler-wardhaugh/clojure/deps.edn
@@ -1,7 +1,8 @@
 {:paths ["src" "resources"]
  :deps {org.clojure/clojure {:mvn/version "1.10.3"}
         clojure.java-time/clojure.java-time {:mvn/version "0.3.3"}
-        org.threeten/threeten-extra {:mvn/version "1.7.0"}}
+        org.threeten/threeten-extra {:mvn/version "1.7.0"}
+        org.clojure/math.numeric-tower {:mvn/version "0.0.4"}}
  :aliases
  {:test {:extra-paths ["test"]
          :extra-deps {org.clojure/test.check {:mvn/version "1.1.0"}
diff --git a/challenge-138/tyler-wardhaugh/clojure/src/tw/weekly/c138/t2.clj b/challenge-138/tyler-wardhaugh/clojure/src/tw/weekly/c138/t2.clj
index ca4530b799..714b0beb42 100644
--- a/challenge-138/tyler-wardhaugh/clojure/src/tw/weekly/c138/t2.clj
+++ b/challenge-138/tyler-wardhaugh/clojure/src/tw/weekly/c138/t2.clj
@@ -1,14 +1,46 @@
 (ns tw.weekly.c138.t2
-  (:require [clojure.edn :as edn]))
+  (:require [clojure.edn :as edn]
+            [clojure.pprint :refer [cl-format]]
+            [clojure.string :as str]
+            [clojure.math.numeric-tower :refer [sqrt expt]]))
 
 ;;;
 ; Task description for TASK #2 › Split Number
 ;;;
 (def DEFAULT-INPUT [81])
 
+(defn ->int
+  [n] (Integer/parseInt n 10))
+
+(defn n->break [len n]
+  (-> n
+      (bit-shift-left 1)
+      (->> (cl-format nil "~v,'0b" len))
+      (str/escape {\1 \+ \0 \-})))
+
+(defn get-splits
+  [n]
+  (let [s (str n)
+        len (count s)
+        breaks (map (partial n->break len) (range 1 (expt 2 (dec len))))
+        join-nums (fn [coll]
+                    (when (not= [\+] coll)
+                      (->> coll (remove #{\-}) (str/join "") ->int)))
+        xf (map (comp (partial keep join-nums)
+                      (partial partition-by #{\+})
+                      (partial interleave s)))]
+    (sequence xf breaks)))
+
+(defn sum-of-splits?
+  [n]
+  (let [source (get-splits n)
+        xf (comp (map (partial reduce +)) (keep #(when (= % (sqrt n)) true)))
+        f (completing (fn [_ v] (reduced v)))]
+    (transduce xf f false source)))
+
 (defn -main
   "Run Task 2 with a given input N, defaulting to the first example from the
   task description."
   [& args]
   (let [[N] (or (some->> args (map edn/read-string)) DEFAULT-INPUT)]
-    ))
+    (println (if (sum-of-splits? N) 1 0))))
diff --git a/challenge-138/tyler-wardhaugh/clojure/test/tw/weekly/c138/t2_test.clj b/challenge-138/tyler-wardhaugh/clojure/test/tw/weekly/c138/t2_test.clj
index 71d2fe47e4..b2a3ef3bb1 100644
--- a/challenge-138/tyler-wardhaugh/clojure/test/tw/weekly/c138/t2_test.clj
+++ b/challenge-138/tyler-wardhaugh/clojure/test/tw/weekly/c138/t2_test.clj
@@ -1,7 +1,9 @@
 (ns tw.weekly.c138.t2-test
   (:require [clojure.test :refer [deftest is testing]]
-            [tw.weekly.c138.t2 :refer []]))
+            [tw.weekly.c138.t2 :refer [sum-of-splits?]]))
 
 (deftest examples
   (testing "Examples from description"
-    ))
+    (is (true? (sum-of-splits? 81)))
+    (is (true? (sum-of-splits? 9801)))
+    (is (false? (sum-of-splits? 36)))))