From abc495ba84ae1a131653ee1b58bfbbc63e423039 Mon Sep 17 00:00:00 2001 From: 4903000 <4903000@chiru.no> Date: Sun, 13 Dec 2020 00:00:54 +0000 Subject: [PATCH] Day 9 --- aoc20.lisp | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 97 insertions(+) diff --git a/aoc20.lisp b/aoc20.lisp index 5c9494f..09b9e88 100644 --- a/aoc20.lisp +++ b/aoc20.lisp @@ -311,3 +311,100 @@ (time (progn (build-graph data) (print (solve-7-1 data symbol)) (print (solve-7-2 symbol)))))) + +;;; day 8 +;;; intcode again + +(defun read-8 (file) + (let ((data (with-open-file (stream file) + (loop for line = (read-line stream nil) + while line + collect (let ((seq (split-sequence:split-sequence #\space line))) + (list (first seq) (parse-integer (second seq)))))))) + (make-array (length data) :initial-contents data))) + +(defun %solve-8 (data &optional alter) + (let* ((accumulator 0) + (position 0) + (ht (make-hash-table)) + (lambdas (list (cons "nop" (lambda (n) (declare (ignore n)) (incf position))) + (cons "acc" (lambda (n) (incf position) (incf accumulator n))) + (cons "jmp" (lambda (n) (incf position n)))))) + (labels ((rec (fiddle-ins) + (cond ((gethash position ht) + (unless alter accumulator)) + ((>= position (length data)) + (values accumulator "EOF")) + (t (progn (setf (gethash position ht) (first (aref data position))) + (funcall (cdr (assoc + (or (if (eql position fiddle-ins) + (if (string= (first (aref data position)) + "nop") + "jmp" "nop") + nil) + (first (aref data position))) + lambdas :test #'equal)) + (second (aref data position))) + (rec fiddle-ins)))))) + (let ((p1 (rec nil)) + (index-list nil)) + (if alter + (progn + (maphash (lambda (k v) (if (or (string= v "nop") (string= v "jmp")) + (push k index-list))) + ht) + (first (remove-if #'null (map 'list (lambda (n) + (setf accumulator 0 + position 0 + ht (make-hash-table)) + (rec n)) + index-list)))) + p1))))) + +(defun solve-8 (file) + (let ((data (read-8 file))) + (time (progn (print (%solve-8 data)) + (print (%solve-8 data t)))))) + +;;; Day 9 + +(defun read-9 (file) + (apply #'vector + (with-open-file (stream file) + (loop for line = (read-line stream nil) + while line + collect (parse-integer line))))) + +(defun step-xmas (seed-size data &optional (index 0)) + (let* ((target (aref data (+ seed-size index))) + (window-list (coerce (subseq data index (+ index seed-size)) 'list)) + (deficits (map 'list (lambda (n) (- target n)) window-list)) + (pairs (intersection deficits window-list))) + ;; (format t "~a, ~a, ~a ~%" target window-list deficits) + (if (< 1 (length pairs)) + pairs target))) + +(defun walk-xmas (seed-size data) + (loop for index from 0 to (- (length data) 1 seed-size) + collecting (step-xmas seed-size data index))) + +(defun solve-9-1 (seed-size data) + (first (remove-if #'consp (walk-xmas seed-size data)))) + +(defun caterpillar (data target tail head) + (let ((range-sum (reduce #'+ (subseq data tail head)))) + (cond ((> target range-sum) + (caterpillar data target tail (1+ head))) + ((< target range-sum) + (caterpillar data target (1+ tail) head)) + (t (subseq data tail head))))) + +(defun solve-9-2 (data target) + (let ((range (sort (caterpillar data target 0 1) #'>))) + (+ (aref range 0) (aref range (1- (length range)))))) + +(defun solve-9 (file &optional (step-size 25)) + (time (let* ((data (read-9 file)) + (p1 (solve-9-1 step-size data))) + (print p1) + (print (solve-9-2 data p1)))))