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corehello/split-nums.lisp

Created March 15, 2017 05:03
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split number to odd list and even list which number is less than n but more than 0
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split-nums.lisp
(defun split-nums (n)
(if (>= n 0)
(if (= n 0)
'((0) NIL)
(if (oddp n)
(map 'list #'append `(NIL (,n)) (split-nums (- n 1)))
(map 'list #'append `((,n) NIL) (split-nums (- n 1)))))))
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 (defun split-nums (n)
	   (if (>= n 0)
	       (if (= n 0)
		   '((0) NIL)
		   (let ((nr (split-nums (- n 1))))
		     (if (oddp n)
			 (list (append NIL (car nr)) (append `(,n) (car (cdr nr))))
			 (list (append `(,n) (car nr)) (append NIL (car (cdr nr)))))))))

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CL-USER> (split-nums 9)
((8 6 4 2 0) (9 7 5 3 1))
CL-USER> (split-nums 13)
((12 10 8 6 4 2 0) (13 11 9 7 5 3 1))
CL-USER> (split-nums 17)
((16 14 12 10 8 6 4 2 0) (17 15 13 11 9 7 5 3 1))
CL-USER> (split-nums 1)
((0) (1))
CL-USER> (split-nums 10)
((10 8 6 4 2 0) (9 7 5 3 1))

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