src/2020/days/day-08.lisp @ 861dab6dff4c
default tip
Clean up last day
author |
Steve Losh <steve@stevelosh.com> |
date |
Wed, 06 Dec 2023 08:56:28 -0500 |
parents |
ff7c8ed35992 |
children |
(none) |
(advent:defpackage* :advent/2020/08)
(in-package :advent/2020/08)
(defun parse-line (line)
(ppcre:register-groups-bind ((#'ensure-keyword op) (#'parse-integer arg))
("^(\\w+) ([-+]\\d+)$" line)
(cons op arg)))
(defclass* console ()
(acc pc mem seen))
(defun make-console (program)
(make-instance 'console
:mem program
:seen (make-array (length program))))
(defun run-console (console)
(setf (acc console) 0
(pc console) 0)
(fill (seen console) nil)
(iterate
(with term = (length (mem console)))
(with seen = (seen console))
(for i = (pc console))
(cond ((= i term) (return :terminated))
((aref seen i) (return :looped))
(t (setf (aref seen i) t)))
(for (op . arg) = (aref (mem console) i))
(incf (pc console))
(ecase op
(:nop)
(:acc (incf (acc console) arg))
(:jmp (incf (pc console) (1- arg))))))
(defun part1 (program)
(let ((console (make-console program)))
(run-console console)
(acc console)))
(defun part2 (program)
(let ((console (make-console program)))
(iterate (for inst :in-vector program)
(for op = (car inst))
(when (member op '(:nop :jmp))
(setf (car inst) (ecase op
(:nop :jmp)
(:jmp :nop)))
(when (eql :terminated (run-console console))
(return-from part2 (acc console)))
(setf (car inst) op)))))
(define-problem (2020 8) (data read-lines) (1217 501)
(let ((program (map 'vector #'parse-line data)))
(values (part1 program)
(part2 program))))
#; Scratch --------------------------------------------------------------------