Ch160 (Clojure): Task 2

2 files changed, 20 insertions, 6 deletions

diff --git a/challenge-160/tyler-wardhaugh/clojure/src/c160/t2.clj b/challenge-160/tyler-wardhaugh/clojure/src/c160/t2.clj
index 06cadecda7..cb7dcc56e3 100644
--- a/challenge-160/tyler-wardhaugh/clojure/src/c160/t2.clj
+++ b/challenge-160/tyler-wardhaugh/clojure/src/c160/t2.clj
@@ -1,12 +1,24 @@
 (ns c160.t2
-  (:require [clojure.edn :as edn]
-            [clojure.pprint :refer [cl-format]]))
+  (:require [clojure.edn :as edn]))
 
-(def DEFAULT-INPUT [])
+(def DEFAULT-INPUT [[1 3 5 7 9]])
+
+(defn splits
+  [coll]
+  (let [v (vec coll)
+        len (count v)]
+    (->> (range len)
+         (map (fn [i] [i (subvec v 0 i) (subvec v (inc i) len)])))))
+
+(defn equilibrium-index
+  [coll]
+  (let [source (splits coll)
+        xf (keep (fn [[i a b]] (when (= (reduce + a) (reduce + b)) i)))]
+    (transduce xf (completing #(reduced %2)) -1 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 (equilibrium-index N))))
diff --git a/challenge-160/tyler-wardhaugh/clojure/test/c160/t2_test.clj b/challenge-160/tyler-wardhaugh/clojure/test/c160/t2_test.clj
index 32273d0178..a15c6ce81e 100644
--- a/challenge-160/tyler-wardhaugh/clojure/test/c160/t2_test.clj
+++ b/challenge-160/tyler-wardhaugh/clojure/test/c160/t2_test.clj
@@ -1,7 +1,9 @@
 (ns c160.t2-test
   (:require [clojure.test :refer [deftest is testing]]
-            [c160.t2 :refer []]))
+            [c160.t2 :refer [equilibrium-index]]))
 
 (deftest task-2
   (testing "Task 2 produces the correct result"
-    ))
+    (is (= 3 (equilibrium-index [1 3 5 7 9])))
+    (is (= -1 (equilibrium-index [1 2 3 4 5])))
+    (is (= 1 (equilibrium-index [2 4 2])))))