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118 lines
3.3 KiB
118 lines
3.3 KiB
;;;; AoC 2020
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(defun read-1 (file)
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(with-open-file (stream file)
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(loop for line = (read-line stream nil)
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while line
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collect (parse-integer line))))
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(defvar *input-1-0* nil)
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(setf *input-1-0* (read-1 "inputs/1-0"))
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(defvar *input-1-1* nil)
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(setf *input-1-1* (read-1 "inputs/1-1.txt"))
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(defun solve-1-1 (data target)
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(let ((deficits (map 'list (lambda (n) (- target n)) data)))
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(reduce #'* (intersection data deficits))))
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(defun make-deficits (list difference)
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(map 'list (lambda (n) (- difference n)) list))
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(defun solve-1-2 (data target)
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(let ((first-deficits (make-deficits data target)))
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(reduce #'*
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(remove-duplicates
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(mapcan (lambda (n)
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(intersection (make-deficits data n) data))
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first-deficits)))))
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(defun solve-1 (data target)
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(time (progn
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(print (solve-1-1 data target))
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(print (solve-1-2 data target)))))
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(defstruct password
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(pchar)
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(prange)
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(word))
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(defun read-2 (file)
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(with-open-file (stream file)
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(loop for line = (read-line stream nil)
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while line
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collect (let* ((pwlist (split-sequence:split-sequence #\space line))
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(range (multiple-value-bind (n index)
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(parse-integer (first pwlist) :junk-allowed t)
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(list n (parse-integer (first pwlist) :start (1+ index))))))
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(make-password
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:pchar (char (second pwlist) 0)
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:prange range
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:word (third pwlist))))))
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(defun %solve-2-1 (pw)
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(let ((n (count (password-pchar pw) (password-word pw))))
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(and (not (> (first (password-prange pw)) n))
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(not (< (second (password-prange pw)) n)))))
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(defun %solve-2-2 (pw)
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(let ((valid 0))
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(loop for index in (password-prange pw)
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do (if (eq (password-pchar pw) (elt (password-word pw) (1- index)))
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(incf valid)))
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(= valid 1)))
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(defun %solve-2 (data test)
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(let ((pn 0))
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(loop for p in data
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do (if (funcall test p)
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(incf pn)))
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pn))
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(defun solve-2 (file)
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(let ((data (read-2 file)))
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(time (progn (print (%solve-2 data #'%solve-2-1))
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(print (%solve-2 data #'%solve-2-2))))))
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(defun read-3 (file)
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(with-open-file (stream file)
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(let ((temp-map (loop for line = (read-line stream nil)
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while line
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collect line)))
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(make-array (list (length temp-map) (length (first temp-map)))
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:initial-contents temp-map
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:element-type 'character))))
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(defun step-slope (position direction map)
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(let* ((temp-position (map 'list #'+ direction position))
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(overflow (map 'list #'> temp-position (array-dimensions map))))
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(cond ((first overflow) :bottom)
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((second overflow)
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(progn (decf (second temp-position) (second (array-dimensions map)))
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temp-position))
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(t temp-position))))
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(defun solve-3-1 (direction map)
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(let ((tree-count 0))
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(labels ((rec (position)
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(let ((zero-pos (map 'list #'1- position))
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(new-pos (step-slope position direction map)))
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(if (char= (aref map (first zero-pos) (second zero-pos))
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#\#)
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(incf tree-count))
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(unless (eq new-pos :bottom)
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(rec new-pos)))))
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(rec '(1 1))
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tree-count)))
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;; (height width)
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(defun solve-3-2 (slopes map)
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(reduce #'* (loop for slope in slopes
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collecting (solve-3-1 slope map))))
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(defun solve-3 (map)
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(time (let ((data (read-3 map)))
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(print (solve-3-1 '(1 3) data))
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(print (solve-3-2 '((1 1) (1 3) (1 5) (1 7) (2 1)) data)))))
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