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15 lines
535 B
15 lines
535 B
2 years ago
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Exercise 2.32: We can represent a set as a list
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of distinct elements, and we can represent the set of all subsets of the set as
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a list of lists. For example, if the set is (1 2 3), then the set of
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all subsets is (() (3) (2) (2 3) (1) (1 3) (1 2) (1 2 3)). Complete the
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following definition of a procedure that generates the set of subsets of a set
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and give a clear explanation of why it works:
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(define (subsets s)
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(if (null? s)
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(list nil)
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(let ((rest (subsets (cdr s))))
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(append rest (map ⟨??⟩ rest)))))
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