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  1. (defun make-math-expr (operand-list)
  2.   (mapcar #'reverse
  3. 	  (reduce (lambda (expr-list operand)
  4. 		    (mapcan (lambda (expr)
  5. 			      (mapcar (lambda (operator)
  6. 					`(,operand ,operator ,@expr))
  7. 				      '(+ - * /)))
  8. 			    expr-list))
  9. 		  (cdr operand-list)
  10. 		  :initial-value `((,(car operand-list))))))
  11.  
  12. (defun math-to-s-expr (expr)
  13.   (mapc (lambda (operator)
  14. 	  (loop with stack
  15. 		for x = (pop expr)
  16. 		while expr
  17. 		do (push (if (find x operator)
  18. 			     (list x (pop stack) (pop expr))
  19. 			     x)
  20. 			 stack)
  21. 		finally (setf expr (nreverse (cons x stack)))))
  22. 	'((* /) (+ -)))
  23.   (car expr))
  24.  
  25. (defun f228 (operand-list answer)
  26.   (format t "~{~a~%~}"
  27. 	  (delete answer (make-math-expr operand-list)
  28. 		  :test-not #'=
  29. 		  :key (lambda (expr) (eval (math-to-s-expr expr))))))
  30.  
  31. (f228 '(1 5 3 6) 10)
  32. (f228 '(1 5 3 6 7) 10)
Success #stdin #stdout 0.03s 10768KB
comments (?)
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Standard input is empty
stdout
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(1 + 5 * 3 - 6)
(1 * 5 / 3 * 6)
(1 + 5 + 3 - 6 + 7)
https://ideone.com/WWVy4P
language:
Common Lisp (clisp 2.49.92)
created:
11 years ago
visibility:
public

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