6 lines
212 B
Racket
6 lines
212 B
Racket
#lang racket
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(define (flatten l)
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(cond [(empty? l) null]
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[(not (list? l)) (list l)]
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[else (append (flatten (first l)) (flatten (rest l)))]))
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(flatten '(1 (2 (3 4 5) (6 7)) 8 9))
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