37 lines
965 B
Common Lisp
37 lines
965 B
Common Lisp
(require :uiop)
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(defun split-instruction (s)
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"Splits a string S into two parts at the given INDEX."
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(cons (subseq s 0 1)
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(subseq s 1)))
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(defun turn-dial (dial instruction)
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(let ((cons-instruction (split-instruction instruction)))
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(let ((op (intern (car cons-instruction)))
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(amount (parse-integer (cdr cons-instruction))))
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(mod
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(funcall
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(cond
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((eql 'L op) #'-)
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((eql 'R op) #'+)
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(t (error "unknown op")))
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dial amount)
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100)
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)
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))
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;; (turn-dial 50 "L68")
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;; (turn-dial 82 "L30")
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;; (turn-dial 52 "R48")
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(defun rec-dial-vm (accum dial lines)
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(let ((instruction (pop lines)))
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(if instruction
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(let ((new-dial (turn-dial dial instruction)))
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(if (= new-dial 0)
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(rec-dial-vm accum new-dial lines)
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(rec-dial-vm (+ 1 accum) new-dial lines)))
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accum)))
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(rec-dial-vm 0 50 (uiop:read-file-lines "01example.txt"))
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(rec-dial-vm 0 50 (uiop:read-file-lines "01data.txt"))
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