Ch218: implement Task 2 in Clojure

3 files changed, 57 insertions, 1 deletions

diff --git a/challenge-218/tyler-wardhaugh/clojure/deps.edn b/challenge-218/tyler-wardhaugh/clojure/deps.edn
index 3d77f22cca..27d77a66a8 100644
--- a/challenge-218/tyler-wardhaugh/clojure/deps.edn
+++ b/challenge-218/tyler-wardhaugh/clojure/deps.edn
@@ -1,5 +1,6 @@
 {:paths ["src" "resources"]
- :deps {org.clojure/clojure {:mvn/version "1.11.1"}}
+ :deps {org.clojure/clojure {:mvn/version "1.11.1"}
+        net.mikera/core.matrix {:mvn/version "0.63.0"}}
  :aliases
  {:t1 {:main-opts ["-m" "c218.t1"]}
   :t2 {:main-opts ["-m" "c218.t2"]}
diff --git a/challenge-218/tyler-wardhaugh/clojure/src/c218/t2.clj b/challenge-218/tyler-wardhaugh/clojure/src/c218/t2.clj
new file mode 100644
index 0000000000..483bc5aa57
--- /dev/null
+++ b/challenge-218/tyler-wardhaugh/clojure/src/c218/t2.clj
@@ -0,0 +1,46 @@
+(ns c218.t2
+  (:require
+    [clojure.edn :as edn]
+    [clojure.core.matrix :as mat]
+    [clojure.string :as str]))
+
+(def DEFAULT-INPUT
+  [[[0 0 1 1]
+    [1 0 1 0]
+    [1 1 0 0]]])
+
+(defn score
+  [m]
+  (-> (map #(-> (map int %) str/join (Long/parseLong 2)))
+      (transduce + 0 (mat/rows m))))
+
+(defn max-matrix-score
+  [coll]
+  (let [m (mat/mutable coll)
+        n-dim (mat/dimension-count m 0)]
+
+    ; maximize rows
+    (loop [[r & rs] (mat/rows m)
+           i 0]
+      (when r
+        (when (zero? (mat/mget r 0))
+          (mat/set-row! m i (mat/eif r 0 1)))
+        (recur rs (inc i))))
+
+    ; maximize columns
+    (loop [[c & cs] (mat/columns m)
+           i 0]
+      (when c
+        (when (and (pos? i)
+                   (<= (mat/non-zero-count c) (quot n-dim 2)))
+          (mat/set-column! m i (mat/eif c 0 1)))
+        (recur cs (inc i))))
+
+    (score m)))
+
+(defn -main
+  "Run Task 2 with a given input COLL, defaulting to the first example from the
+  task description."
+  [& args]
+  (let [[coll] (or (some->> args (map edn/read-string)) DEFAULT-INPUT)]
+    (println (max-matrix-score coll))))
diff --git a/challenge-218/tyler-wardhaugh/clojure/test/c218/t2_test.clj b/challenge-218/tyler-wardhaugh/clojure/test/c218/t2_test.clj
new file mode 100644
index 0000000000..371c8596f4
--- /dev/null
+++ b/challenge-218/tyler-wardhaugh/clojure/test/c218/t2_test.clj
@@ -0,0 +1,9 @@
+(ns c218.t2-test
+  (:require [clojure.test :refer [deftest is testing]]
+            [c218.t2 :refer [max-matrix-score]]))
+
+(deftest task-2
+  (testing "Task 2 produces the correct results from examples in the description"
+    (is (= 39 (max-matrix-score [[0 0 1 1]
+                                 [1 0 1 0]
+                                 [1 1 0 0]])))))