2023-05-08 07:48:56 -04:00
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(define (first x) (car x))
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(define (second x) (cadr x))
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(define (third x) (caddr x))
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(define (last x)
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(if (null? (cdr x))
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(car x)
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(last (cdr x))))
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2023-05-05 17:37:04 -04:00
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(define (caar x) (car (car x)))
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(define (cadr x) (car (cdr x)))
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(define (cdar x) (cdr (car x)))
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(define (cddr x) (cdr (cdr x)))
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(define (caaar x) (car (car (car x))))
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(define (caadr x) (car (car (cdr x))))
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(define (cadar x) (car (cdr (car x))))
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(define (caddr x) (car (cdr (cdr x))))
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(define (cdaar x) (cdr (car (car x))))
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(define (cdadr x) (cdr (car (cdr x))))
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(define (cddar x) (cdr (cdr (car x))))
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(define (cdddr x) (cdr (cdr (cdr x))))
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(define (caaaar x) (car (car (car (car x)))))
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(define (caaadr x) (car (car (car (cdr x)))))
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(define (caadar x) (car (car (cdr (car x)))))
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(define (caaddr x) (car (car (cdr (cdr x)))))
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(define (cadaar x) (car (cdr (car (car x)))))
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(define (cadadr x) (car (cdr (car (cdr x)))))
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(define (caddar x) (car (cdr (cdr (car x)))))
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(define (cadddr x) (car (cdr (cdr (cdr x)))))
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(define (cdaaar x) (cdr (car (car (car x)))))
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(define (cdaadr x) (cdr (car (car (cdr x)))))
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(define (cdadar x) (cdr (car (cdr (car x)))))
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(define (cdaddr x) (cdr (car (cdr (cdr x)))))
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(define (cddaar x) (cdr (cdr (car (car x)))))
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(define (cddadr x) (cdr (cdr (car (cdr x)))))
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(define (cdddar x) (cdr (cdr (cdr (car x)))))
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(define (cddddr x) (cdr (cdr (cdr (cdr x)))))
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2023-05-05 17:40:16 -04:00
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(define (list-tail x k)
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(if (zero? k)
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x
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(list-tail (cdr x) (- k 1))))
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(define (list-ref x k) (car (list-tail x k)))
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