20 lines
396 B
Scheme
20 lines
396 B
Scheme
#lang scheme/base
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(provide (all-defined-out))
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(define (assoc-remove k l)
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(cond
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((null? l) '())
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((eq? (car (car l)) k)
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(assoc-remove k (cdr l)))
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(else
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(cons (car l) (assoc-remove k (cdr l))))))
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(define (choose l)
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(list-ref l (random (length l))))
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(define (list-contains k l)
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(cond
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((null? l) #f)
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((eq? (car l) k) #t)
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(else (list-contains k (cdr l)))))
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