From f8a0d0f1acc50711e470999434f7f8f504188b2e Mon Sep 17 00:00:00 2001 From: Aryadev Chavali Date: Mon, 26 Jun 2023 07:16:31 +0100 Subject: (1|2)+lisp files for puzzles 1 and 2 Includes code for both rounds, separated by comments. --- puzzle-2.lisp | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 puzzle-2.lisp (limited to 'puzzle-2.lisp') diff --git a/puzzle-2.lisp b/puzzle-2.lisp new file mode 100644 index 0000000..377b6ba --- /dev/null +++ b/puzzle-2.lisp @@ -0,0 +1,54 @@ +(defvar input (uiop:read-file-string "puzzle-2-input.txt")) +;; Each newline represents a new round, which we should parse on the go + +(defun sensible-convert-input (str) + (cond + ((or (string= str "X") (string= str "A")) 0) + ((or (string= str "Y") (string= str "B")) 1) + ((or (string= str "Z") (string= str "C")) 2))) + +;; Round 1 +(defvar rounds + (with-input-from-string (stream input) + (loop + for strategy = (read-line stream nil) + until (null strategy) + collect + (let ((opponent (subseq strategy 0 1)) + (yours (subseq strategy 2 3))) + (list (sensible-convert-input opponent) (sensible-convert-input yours)))))) + +(loop + for round in rounds + until (null round) + sum + (destructuring-bind (opp you) round + (+ + 1 you ;; base score + (cond ; outcome score + ((eq you opp) 3) + ((eq (mod (+ 1 opp) 3) you) 6) + (t 0))))) + +;; Round 2. + +;; We can still use the same rounds data as previously, just +;; reinterpret it in when doing the sum. + +(defun get-correct-choice (opponent outcome) + (case outcome + (0 (mod (- opponent 1) 3)) + (1 opp) + (2 (mod (+ 1 opponent) 3)) + (t 0))) + +(loop for round in rounds + sum + (destructuring-bind (opp you) round + (let ((choice (get-correct-choice opp you))) + (+ 1 choice + (case you ;; outcome -> score + (0 0) + (1 3) + (2 6) + (t 0)))))) -- cgit v1.2.3-13-gbd6f