June 2018 Update

Task/N-queens-problem/Clojure/n-queens-problem-1.clj

@@ -0,0 +1,23 @@
+(def size 8)
+
+(defn extends? [v n]
+  (let [k (count v)]
+    (not-any? true?
+      (for [i (range k) :let [vi (v i)]]
+        (or
+          (= vi n)  ;check for shared row
+          (= (- k i) (Math/abs (- n vi)))))))) ;check for shared diagonal
+
+(defn extend [vs]
+  (for [v vs
+        n (range 1 (inc size)) :when (extends? v n)]
+    (conj v n)))
+
+
+(def solutions
+  (nth (iterate extend [[]]) size))
+
+(doseq [s solutions]
+  (println s))
+
+(println (count solutions) "solutions")