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valvallow/Combination2.scm

Created February 10, 2010 11:51
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combination
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Combination2.scm
(define combination
(lambda (r l)
(cond
((null? l) '())
((or (zero? r)(> r (length l))) '())
((= r 1)(map list l))
((= r (length l))(list l))
(else (append (map (lambda (n)(cons (car l) n))
(combination (- r 1)(cdr l)))
(combination r (cdr l)))))))
(combination 5 '(a b c d e f g))
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