src/utilities.lisp

   1 (in-package #:adventofcode2020)
   2
   3 ;;; Utility functions
   4
   5 (defun list-from (str)
   6   (split "\\n" str))
   7
   8 (defun int-list-from (str)
   9   (mapcar #'parse-integer (split "\\n" str)))
  10
  11 (defun cartesian-product (A B &rest C)
  12   (let ((helper (lambda (X Y)
  13                   (if Y (loop for x in X
  14                               nconc (loop for y in Y
  15                                           collecting (append x (list y))))
  16                       X)))
  17         (wrap-A (mapcar #'list A)))
  18     (reduce helper C :initial-value (funcall helper wrap-A B))))
  19
  20 (def-suite util)
  21 (in-suite util)
  22
  23 (test cart-prod-2
  24   (is (equal
  25         '((a a) (a b) (b a) (b b))
  26         (cartesian-product '(a b) '(a b)))))
  27
  28 (test cart-prod-3
  29   (is (equal
  30         '((a a a) (a a b) (a b a) (a b b)
  31                   (b a a) (b a b) (b b a) (b b b))
  32         (cartesian-product '(a b) '(a b) '(a b)))))
  33
  34 (test cart-prod-4
  35   (is (equal
  36         '((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)
  37                     (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))
  38         (cartesian-product '(a b) '(a b) '(a b) '(a b)))))
  39
  40