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19 lines
802 B
19 lines
802 B
3 years ago
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Exercise 2.36: The procedure accumulate-n
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is similar to accumulate except that it takes as its third argument a
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sequence of sequences, which are all assumed to have the same number of
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elements. It applies the designated accumulation procedure to combine all the
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first elements of the sequences, all the second elements of the sequences, and
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so on, and returns a sequence of the results. For instance, if s is a
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sequence containing four sequences, ((1 2 3) (4 5 6) (7 8 9) (10 11
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12)), then the value of (accumulate-n + 0 s) should be the sequence
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(22 26 30). Fill in the missing expressions in the following definition
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of accumulate-n:
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(define (accumulate-n op init seqs)
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(if (null? (car seqs))
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nil
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(cons (accumulate op init ⟨??⟩)
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(accumulate-n op init ⟨??⟩))))
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