- ;; mht created on Nov 15, 2011
-
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;; dollar-store? : list-of-numbers -> boolean
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;; to check whether all of a-list-of-nums are < 1
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(define (dollar-store? a-list-of-nums)
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(cond
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[(empty? a-list-of-nums) true]
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[else
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(and
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(< (first a-list-of-nums) 1)
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(dollar-store? (rest a-list-of-nums)))]))
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;; test
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(dollar-store? empty)
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(not (dollar-store? (cons .75 (cons 1.95 (cons .25 empty)))))
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(dollar-store? (cons .15 (cons .05 (cons .25 empty))))
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;; generalized-dollar-store? : list-of-numbers number -> boolean
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;; to check whether all of a-list-of-nums are below n
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(define (generalized-dollar-store? a-list-of-nums n)
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(cond
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[(empty? a-list-of-nums) true]
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[else
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(and
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(< (first a-list-of-nums) n)
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(generalized-dollar-store? (rest a-list-of-nums) n))]))
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;; test
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(generalized-dollar-store? empty 1)
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(not (generalized-dollar-store? (cons .75 (cons 1.95 (cons .25 empty))) 1))
- (generalized-dollar-store? (cons .15 (cons .05 (cons .25 empty))) 1)
