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    <p>There are two things you should think about here. The first is the one you mentioned-- that you could have either <code>a</code> or <code>(1 a)</code>, both meaning the same thing. You probably want to move that into <code>expandHelper</code>, so it looks more like <code>(expandHelper value)</code>, and then you should switch on whether it's a list or a symbol.</p> <p>The second is in how you're calling <code>expandHelper</code>. If you feed in a list like <code>'(a (3 b) (3 a) b (2 c) (3 a))</code> to <code>expand</code>, it'll currently call <code>(expandHelper a (3 b))</code>, which is probably not what you had in mind. Instead, you want to make sure you call <code>expandHelper</code> on every element of the list, and <code>cons</code> together the results. You can do that by calling <code>expandHelper</code> on the first element of the list, and then recursively calling <code>expand</code> on the remainder of the list.</p> <p>I haven't checked to see that this compiles, it's just the general idea:</p> <pre><code>(define (expandHelper value) (if (list? value) ;; means value is something like (2 a) (if (= 0 (car value)) ;; then (car value) is 2 '() ;; if it's zero, we complete the list and return! (cons (cadr value) ;;otherwise, we append (cadr value) = a to... (expandHelper (cons (- (car value) 1) (cadr value)))))) ;; the result of expand helper on (- (car value) 1) = 1 ;; and (cadr value) = a (cons value '()))) ;; if it's not a list, we should just return the value. </code></pre>
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    1. POscheme expand function
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    1. COThis is what I was thinking too, but, I'm not sure how to implement it. Im new to Scheme and a bit confused too. Im not sure how to change expandHelper.
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