(split "\\n" str))
(defun int-list-from (str)
- (mapcar #'parse-integer (split "\\n" str)))
+ (mapcar #'parse-integer (list-from str)))
+
+(defun cartesian-product (A B &rest C)
+ (let ((helper (lambda (X Y)
+ (if Y (loop for x in X
+ nconc (loop for y in Y
+ collecting (append x (list y))))
+ X)))
+ (wrap-A (mapcar #'list A)))
+ (reduce helper C :initial-value (funcall helper wrap-A B))))
+
+(def-suite util)
+(in-suite util)
+
+(test cart-prod-2
+ (is (equal
+ '((a a) (a b) (b a) (b b))
+ (cartesian-product '(a b) '(a b)))))
+
+(test cart-prod-3
+ (is (equal
+ '((a a a) (a a b) (a b a) (a b b)
+ (b a a) (b a b) (b b a) (b b b))
+ (cartesian-product '(a b) '(a b) '(a b)))))
+
+(test cart-prod-4
+ (is (equal
+ '((a a a a) (a a a b) (a a b a) (a a b b) (a b a a) (a b a b) (a b b a) (a b b b)
+ (b a a a) (b a a b) (b a b a) (b a b b) (b b a a) (b b a b) (b b b a) (b b b b))
+ (cartesian-product '(a b) '(a b) '(a b) '(a b)))))
+
+