63 lines
1.4 KiB
Common Lisp
63 lines
1.4 KiB
Common Lisp
;; Day 3: Perfectly Spherical Houses in a Vacuum
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;;
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;; Part 1: How many houses recieve at least one present?
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(defun move (char)
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(cond
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((equal char #\>)
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(list 1 0))
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((equal char #\^)
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(list 0 -1))
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((equal char #\<)
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(list -1 0))
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((equal char #\v)
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(list 0 1))
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(t nil)
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))
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(defparameter *houses* (make-hash-table :test 'equal))
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(defparameter visited-houses-counter 0)
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(defun visit (house)
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(if (gethash house *houses*)
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"key exist"
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(progn
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(setf visited-houses-counter (+ visited-houses-counter 1))
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(setf (gethash house *houses*) 1))))
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(defparameter xsanta 0)
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(defparameter ysanta 0)
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(defparameter xrobot 0)
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(defparameter yrobot 0)
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(visit (list 0 0))
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(defparameter i 0)
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(defvar walk)
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(defun make-move (char)
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(setq walk (move char))
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(setq i (+ i 1))
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(if (= 0 (mod i 2))
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(progn
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(setf xrobot (+ xrobot (nth 0 walk)))
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(setf yrobot (+ yrobot (nth 1 walk)))
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(visit (list xrobot yrobot)))
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(progn
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(setf xsanta (+ xsanta (nth 0 walk)))
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(setf ysanta (+ ysanta (nth 1 walk)))
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(visit (list xsanta ysanta)))))
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(with-open-file (in "./data/input")
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(do ((c (read-char in)
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(read-char in nil 'the-end)))
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((not (characterp c)))
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(if (not (equal c #\Newline))
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(make-move c))))
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(print visited-houses-counter)
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