src/2018/days/day-14.lisp @ 08dd2b57f2c0
2021/03
author |
Steve Losh <steve@stevelosh.com> |
date |
Fri, 03 Dec 2021 12:36:07 -0500 |
parents |
182bdd87fd9e |
children |
(none) |
(advent:defpackage* :advent/2018/14)
(in-package :advent/2018/14)
(defun combine (recipes elves)
(digits (summation elves :key (curry #'aref recipes))))
(defun move-elves (recipes elves)
(do-array (elf elves)
(setf elf (mod (+ elf (aref recipes elf) 1)
(length recipes)))))
(defun format-output (scores)
(str:join "" (map 'list #'aesthetic-string scores)))
(define-problem (2018 14) (data read) ("3610281143" 20211326)
#+sbcl (sb-ext:gc :full t)
(iterate
(with recipes = (make-array 2
:adjustable t
:fill-pointer t
:initial-contents '(3 7)))
(with elves = (make-array 2 :initial-contents '(0 1)))
(with part-1 = nil)
(with part-2 = nil)
(with target = (digits data :result-type 'vector))
(with target-length = (length target))
(until (and part-1 part-2))
(unless part-1
(when (>= (length recipes) (+ 10 data))
(setf part-1 (format-output (subseq recipes data (+ data 10))))))
(iterate (for new-recipe :in (combine recipes elves))
(vector-push-extend new-recipe recipes)
(for len = (length recipes))
(for left = (- len target-length))
(unless part-2
(when (and (not (minusp left))
(search target recipes :start2 left))
(setf part-2 left))))
(move-elves recipes elves)
(finally (return (values part-1 part-2)))))