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(defun input-lines (f)
(with-open-file (s f)
(loop for line = (read-line s nil 'eof)
until (eq line 'eof)
collect line)))
(defun check-set (string red green blue)
(multiple-value-bind (n begin)
(parse-integer string :junk-allowed t)
(cond ((search "red" string :start2 begin) (<= n red))
((search "green" string :start2 begin) (<= n green))
((search "blue" string :start2 begin) (<= n blue)))))
(defun split-by-char (char string)
(loop for i = 0 then (1+ j)
as j = (position char string :start i)
collect (subseq string i j)
while j))
(defun check-round (string red green blue)
(let ((sets (split-by-char #\, string)))
(not (find-if-not (lambda (set) (check-set set red green blue)) sets))))
(defun check-game (string red green blue)
(let ((pstring (nth 1 (split-by-char #\: string))))
(let ((rounds (split-by-char #\; pstring)))
(not (find-if-not (lambda (set) (check-round set red green blue)) rounds)))))
(defun solve1 (f)
(loop for line in (input-lines f)
as gid = (parse-integer line :junk-allowed t :start 5)
when (check-game line 12 13 14)
sum gid))
(defun cube-count (string color)
(multiple-value-bind (n begin)
(parse-integer string :junk-allowed t)
(if (search color string :start2 begin) n 0)))
(defun game-max-cubes (line color)
(loop for i = (1+ (position #\: line)) then (1+ j)
as j = (position-if (lambda (c) (or (equal c #\,) (equal c #\;))) line :start i)
as count = (cube-count (subseq line i j) color)
maximize count
while j))
(defun solve2 (f)
(loop for line in (input-lines f)
as r = (game-max-cubes line "red")
as g = (game-max-cubes line "green")
as b = (game-max-cubes line "blue")
sum (* r g b)))
(print (solve1 "data/02/example.txt"))
(print (solve1 "data/02/input.txt"))
(print (solve2 "data/02/example.txt"))
(print (solve2 "data/02/input.txt"))
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