19 lines
425 B
Racket
19 lines
425 B
Racket
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#lang racket
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(define (list-length list)
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(match list
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[`() 0]
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[(cons head tail) (cons (f head)
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(list-length f tail))]))
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(module+ test
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(require rackunit)
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(check-equal? (list-length '(1 2 3)) 3)
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(check-equal? (list-length '()) 0))
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(define (my-map2 f lst)
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(match lst
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['() '()]
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[(list head tail ...) (cons (f head)
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(my-map2 f tail))]))
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