all tasks

Task/Sudoku/Clojure/sudoku-1.clj

@@ -0,0 +1,41 @@
+(ns sudoku
+  (:use [clojure.contrib.math :only (sqrt)]))
+
+(defn print-grid [grid]
+  (doseq [y (range (count grid))]
+    (doseq [x (range (count grid))]
+      (print (retrieve grid x y) " "))
+    (println))
+  (println))
+
+(defn retrieve [grid x y]
+  (get (get grid y) x))
+
+(defn store [grid x y n]
+  (assoc grid y (assoc (get grid y) x n)))
+
+(defn coordinates [grid x y]
+  (let [n (sqrt (count grid))
+        zx (* n (quot x n))
+        zy (* n (quot y n))]
+    (for [x (range zx (+ zx n)) y (range zy (+ zy n))]
+      [x y])))
+
+(defn compatible? [grid x y n]
+  (or
+   (= n (retrieve grid x y))
+   (and
+    (zero? (retrieve grid x y))
+    (every? #(and (not= n (retrieve grid % y)) (not= n (retrieve grid x %))) (range (count grid)))
+    (every? #(not= n (retrieve grid (first %) (second %))) (coordinates grid x y)))))
+
+(defn solve [grid x y]
+  (let [m (count grid)]
+    (if (= y m)
+      (print-grid grid)
+      (doseq [n (range 1 (inc m))]
+        (when (compatible? grid x y n)
+          (let [new-grid (store grid x y n)]
+            (if (= x (dec m))
+              (solve new-grid 0 (inc y))
+              (solve new-grid (inc x) y))))))))

Task/Sudoku/Clojure/sudoku-2.clj

@@ -0,0 +1,21 @@
+sudoku> (solve [[3 9 4 0 0 2 6 7 0]
+               [0 0 0 3 0 0 4 0 0]
+               [5 0 0 6 9 0 0 2 0]
+               [0 4 5 0 0 0 9 0 0]
+               [6 0 0 0 0 0 0 0 7]
+               [0 0 7 0 0 0 5 8 0]
+               [0 1 0 0 6 7 0 0 8]
+               [0 0 9 0 0 8 0 0 0]
+               [0 2 6 4 0 0 7 3 5]]
+               0 0)
+3  9  4  8  5  2  6  7  1
+2  6  8  3  7  1  4  5  9
+5  7  1  6  9  4  8  2  3
+1  4  5  7  8  3  9  6  2
+6  8  2  9  4  5  3  1  7
+9  3  7  1  2  6  5  8  4
+4  1  3  5  6  7  2  9  8
+7  5  9  2  3  8  1  4  6
+8  2  6  4  1  9  7  3  5
+
+nil