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 (list-from str)))
  10
  11 (defun list-list-from (str)
  12   (split-sequence "" (list-from str) :test #'string=))
  13
  14 (defun cartesian-product (A B &rest C)
  15   (let ((helper (lambda (X Y)
  16                   (if Y (loop for x in X
  17                               nconc (loop for y in Y
  18                                           collecting (append x (list y))))
  19                       X)))
  20         (wrap-A (mapcar #'list A)))
  21     (reduce helper C :initial-value (funcall helper wrap-A B))))
  22
  23 (def-suite util)
  24 (in-suite util)
  25
  26 (test cart-prod-2
  27   (is (equal
  28         '((a a) (a b) (b a) (b b))
  29         (cartesian-product '(a b) '(a b)))))
  30
  31 (test cart-prod-3
  32   (is (equal
  33         '((a a a) (a a b) (a b a) (a b b)
  34                   (b a a) (b a b) (b b a) (b b b))
  35         (cartesian-product '(a b) '(a b) '(a b)))))
  36
  37 (test cart-prod-4
  38   (is (equal
  39         '((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)
  40                     (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))
  41         (cartesian-product '(a b) '(a b) '(a b) '(a b)))))
  42
  43