src/2017/days/day-11.lisp @ 2848a4548adf
2023/01 and 2022/01
Also start porting my test data to the new account, since Twitter imploded and
apparently it's impossible for a website to store a goddamn username and
password in The Year of Our Lord 2023 so everyone just outsources auth all
the time, ugh.
author |
Steve Losh <steve@stevelosh.com> |
date |
Fri, 01 Dec 2023 11:05:43 -0500 (13 months ago) |
parents |
182bdd87fd9e |
children |
(none) |
(advent:defpackage* :advent/2017/11)
(in-package :advent/2017/11)
;; https://www.redblobgames.com/grids/hexagons/#coordinates
(defun coord+ (c1 c2)
(map 'vector #'+ c1 c2))
(defun coord- (c1 c2)
(map 'vector #'- c1 c2))
(defun distance (c1 &optional (c2 #(0 0 0)))
(/ (reduce #'+ (coord- c1 c2) :key #'abs) 2))
(defun delta (direction)
(ecase direction
(:nw #(-1 0 1))
(:n #( 0 -1 1))
(:ne #( 1 -1 0))
(:se #( 1 0 -1))
(:s #( 0 1 -1))
(:sw #(-1 1 0))))
(define-problem (2017 11) (data read-comma-separated-values) (773 1560)
(iterate
(with pos = #(0 0 0))
(for direction :in (mapcar #'ensure-keyword data))
(setf pos (coord+ pos (delta direction)))
(maximizing (distance pos) :into furthest)
(finally (return (values (distance pos) furthest)))))