AoC 2023

2b.lisp

(require 'asdf)
(require 'alexandria)
(require 'cl-ppcre)
(defparameter inp "467..114..
...*......
..35..633.
......#...
617*......
.....+.58.
..592.....
......755.
...$.*....
.664.598..")
; (defparameter inp (alexandria:read-file-into-string "3/inp.txt"))
(defparameter inp-lines (split-sequence:split-sequence #\Newline inp))
(defparameter len (length inp-lines))

(defparameter nums-re "[0-9]+")
(defparameter syms-re "[^0-9\.]")
(defun idx-tuple (line match)
    (let ((start (car match)) (end (car (cdr match))))
        (list (subseq line start end) start end)))
(defun idx-tuples (line matches) (if matches
                                     (cons (idx-tuple line (subseq matches 0 2))
                                           (idx-tuples line (cddr matches)))))
(defun matches-on-line (line re) (idx-tuples line (cl-ppcre:all-matches re line)))
(defparameter syms (mapcar (alexandria:rcurry #'matches-on-line syms-re) inp-lines))
(defparameter nums (mapcar (alexandria:rcurry #'matches-on-line nums-re) inp-lines))
(defun adj-nums (line-idx)
        (apply #'append (subseq nums (max (- line-idx 1) 0) (min (+ line-idx 1) len))))
(defun match-s (match) (car match))
(defun match-start (match) (cadr match))
(defun match-end (match) (caddr match))

(defun sym-is-adj (sym num)
    (if (or (>= (match-end num) (- (match-start sym) 1))
                      (<= (match-start num) (match-start sym)))
        (parse-integer (match-s num))))
(trace sym-is-adj)

(defun myratio (line-idx sym)
    (let ((numss (adj-nums line-idx))
           (adj-to-num (alexandria:curry #'sym-is-adj sym)))
           (loop for num in numss and num-idx from 0
                                when (funcall adj-to-num num)
                                collect (funcall adj-to-num num))))
(trace myratio)
(defun ratios-on-line (syms-on-line line-idx)
    (loop for sym in syms-on-line
              with res = (and sym (myratio line-idx sym))
              when (and res (= 2 (length res)))
              collect res))
    
              
; (defparameter out-messy (loop for syms-on-line in syms and line-idx from 0
;           with res = (myratio line-idx syms-on-line)
;           when (= 2 (length res))
;           collect (parts-on-line nums-on-line line-idx)))
(defparameter out (apply #'+ (mapcar #'parse-integer (apply #'append out-messy))))