(in-package #:adventofcode2020)

(defun calculate-expenses (&rest reports)
  (let ((prod (apply #'cartesian-product reports)))
    (loop for tuple in prod
          when (= (apply #'+ tuple) 2020)
          return (apply #'* tuple))))

(day 01 input
  (let ((report (int-list-from input)))
    (part1 (calculate-expenses report report))
    (part2 (calculate-expenses report report report))))

(def-suite day01)
(in-suite day01)

(test simple-expenses
  (is (equal
        514579
        (let ((report '(1721 979 366 299 675 1456)))
          (calculate-expenses report report)))))

(test complex-expenses
  (is (equal
        241861950
        (let ((report '(1721 979 366 299 675 1456)))
          (calculate-expenses report report report)))))

(run! 'day01)