61 lines
2.4 KiB
Common Lisp
61 lines
2.4 KiB
Common Lisp
(defun ten-to-bin (x len)
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"Создает вектор бит фиксированной длины (аналог маски)."
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(let ((mask (make-array len :element-type 'bit :initial-element 0)))
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(loop for i from (1- len) downto 0
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while (> x 0)
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do (multiple-value-bind (quotient remainder) (truncate x 2)
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(setf (aref mask i) remainder)
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(setf x quotient)))
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mask))
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(defun calculate-sum (numbers-vec mask-vec)
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"Считает сумму элементов вектора по маске. Использует across для векторов."
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(loop for num across numbers-vec
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for flag across mask-vec
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when (= flag 1)
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sum num))
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(defun find-sum (target numbers-vec)
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(declare (optimize (speed 3) (safety 0) (debug 0))
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(type (simple-array fixnum (*)) numbers-vec)
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(type fixnum target))
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(let* ((len (length numbers-vec))
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(total (1- (ash 1 len)))
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(current-sum 0)
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;; Массив для отслеживания текущего состояния (биты)
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(bits (make-array len :element-type 'bit :initial-element 0)))
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(declare (type fixnum current-sum))
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(format t "Combinations: ~D~%" total)
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;; Итерация по Коду Грея
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(loop for i fixnum from 1 to total do
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(let* ((gray-diff (logand i (- i))) ; Находим индекс изменяемого бита
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(bit-idx (1- (integer-length gray-diff)))
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(num (aref numbers-vec bit-idx)))
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(declare (type fixnum bit-idx num))
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;; Если бит был 0, прибавляем число, если 1 — вычитаем
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(if (zerop (aref bits bit-idx))
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(progn
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(incf current-sum num)
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(setf (aref bits bit-idx) 1))
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(progn
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(decf current-sum num)
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(setf (aref bits bit-idx) 0)))
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;; Проверка цели
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(when (= current-sum target)
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(format t "Found: ~A~%" bits)
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(return-from find-sum bits))))
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nil))
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(defun main (args)
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(let ((len (length args)))
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(if (or (< len 5) (> len 30))
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(progn
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(format t "ER: input parameters~%")
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(uiop:quit 1))
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(let* ((target (parse-integer (first args)))
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(numbers-vec (coerce (mapcar #'parse-integer (rest args)) 'vector)))
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(find-sum target numbers-vec)))))
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