12 lines
352 B
Racket
12 lines
352 B
Racket
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#lang racket
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;; insert b after a in a mutable list (assumes that a is in the input list)
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(define (insert-after! list a b)
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(if (equal? (mcar list) a)
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(set-mcdr! list (mcons b (mcdr list)))
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(insert-after! (mcdr list) a b)))
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(define l (mcons 1 (mcons 2 (mcons 3 '()))))
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(insert-after! l 2 2.5)
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l ; -> (mcons 1 (mcons 2 (mcons 2.5 (mcons 3))))
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