Initial data commit

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")

Task/N-queens-problem/Clojure/n-queens-problem-2.clj

@@ -0,0 +1,6 @@
+(ns queens
+  (:require [clojure.math.combinatorics :as combo]
+
+(defn queens [n]
+  (filter (fn [x] (every? #(apply distinct? (map-indexed % x)) [+ -]))
+          (combo/permutations (range 1 (inc n)))))

Task/N-queens-problem/Clojure/n-queens-problem-3.clj

@@ -0,0 +1,9 @@
+  (defn n-queens [n]
+    (let[children #(map (partial conj %) (range n))
+         no-conflict? (fn [x] (or (empty? x)
+                                  (every? #(apply distinct? (map-indexed % x))
+                                          [+ - (fn[_ v] v)])))]
+      (filter (every-pred no-conflict? #(= n (count %)))
+              (tree-seq (every-pred #(> n (count %))
+                                    no-conflict?)
+                        children []))))