Day 7: Bridge Repair
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View all comments 2 points
Lisp
Could probably go much faster if I kept track of calculations to not repeat, but 4 seconds for part 2 on my old laptop is good enough for me. Also, not really a big change from part 1 to part 2.
Part 1 and 2
(defstruct calibration result inputs)
(defun p1-process-line (line)
(let ((parts (str:words line)))
(make-calibration :result (parse-integer (car parts) :junk-allowed t)
:inputs (mapcar #'parse-integer (cdr parts)))))
(defun apply-opperators (c opps)
(let ((accum (car (calibration-inputs c))))
(loop for o in opps
for v in (cdr (calibration-inputs c))
until (> accum (calibration-result c))
if (eql o 'ADD)
do (setf accum (+ accum v))
else if (eql o 'MUL)
do (setf accum (* accum v))
else
do (setf accum (+ v (* accum (expt 10 (1+ (floor (log v 10)))))))
finally (return accum)
)))
(defun generate-operators (item-count)
(labels ((g-rec (c results)
(if (< c 1)
results
(g-rec (1- c) (loop for r in results
collect (cons 'ADD r)
collect (cons 'MUL r))))))
(g-rec (1- item-count) '((ADD) (MUL)))))
(defun generate-ops-hash (c gen-ops)
(let ((h (make-hash-table)))
(dotimes (x c)
(setf (gethash (+ 2 x) h) (funcall gen-ops (+ 1 x))))
h))
(defun validate-calibration (c ops-h)
(let ((r (calibration-result c))
(ops (gethash (length (calibration-inputs c)) ops-h)))
(loop for o in ops
for v = (apply-opperators c o)
when (= v r)
return t)))
(defun run-p1 (file)
(let ((calibrations (read-file file #'p1-process-line))
(ops (generate-ops-hash 13 #'generate-operators)))
(loop for c in calibrations
when (validate-calibration c ops)
sum (calibration-result c))))
(defun generate-operators-p2 (item-count)
(labels ((g-rec (c results)
(if (< c 1)
results
(g-rec (1- c) (loop for r in results
collect (cons 'ADD r)
collect (cons 'MUL r)
collect (cons 'CAT r))))))
(g-rec (1- item-count) '((ADD) (MUL) (CAT)))))
(defun run-p2 (file)
(let ((calibrations (read-file file #'p1-process-line))
(ops (generate-ops-hash 13 #'generate-operators-p2)))
(loop for c in calibrations
when (validate-calibration c ops)
sum (calibration-result c))))
