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Do part 2 and cleanup day06

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This commit is contained in:
Felix Albrigtsen 2022-12-06 10:18:45 +01:00
parent f451ac9b1e
commit 10eebfbf75
1 changed files with 16 additions and 10 deletions
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26
day06/main.lisp
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@ -1,20 +1,26 @@
(defun string-to-list (s)
(assert (stringp s) (s) "~s :questa non e una stringa")
(coerce s 'list))
; Split to list, remove duplicates, recombine
(defun unique-string (str)
(concatenate 'string (remove-duplicates (string-to-list str))))
(concatenate 'string (remove-duplicates (coerce str 'list))))
(defun unique-sequence (str n)
(if (= (length (unique-string (subseq str 0 n))) n)
(subseq str 0 n)
(unique-sequence (subseq str 1) n)))
; Returns the index of the first occurrence of a sequence of "len" different characters in "str"
(defun unique-sequence (str len &optional (offset 0))
(if (= len
(length (unique-string (subseq str offset (+ len offset)))))
offset
(unique-sequence str len (+ offset 1))))
; unique-sequence gives the index-of, but we want the index-after
(defun part1 (str)
(+ 4 (search (unique-sequence str 4) str)))
(+ 4 (unique-sequence str 4)))
(defun part2 (str)
(+ 14 (unique-sequence str 14)))
(let ((in (open "input.txt" :if-does-not-exist nil)))
(when in
(print (part1 (read-line in)))
(let ((str (read-line in nil nil)))
(format t "Part 1: ~a~%" (part1 str))
(format t "Part 2: ~a~%" (part2 str)))
(close in)))