[plt-scheme] Excersise 14.2.3 - HtDP - Ordered list of binary tree nodes

From: Matthias Felleisen (matthias at ccs.neu.edu)
Date: Fri Feb 20 19:21:14 EST 2009

I am taking the liberty of replying in public:

On Feb 20, 2009, at 6:12 PM, Charlie Turner wrote:

> And Matthias. Thank you for your suggestion to use such a table. It
> was this that finally allowed me to see the solution. I learned that
> instead of trying to hold all the details in my head (which clearly
> doesn't work) I should write down what is happening every time I call
> my definition on new data.

While I used to do this informally on occasion (see below),
Felix Klock deserves the full credit for insisting that we
always do this and do it in a tabular format. It helps a lot.

> I must say I wasn't using the Deisng Recipies quite has rigourosly as
> I should have. Up until now I've been lazy with the excersises. I
> think this is because there weren't as many parts to think about as
> there are now, with the binary trees, and I've been allowed to get
> sloppy. The recursion in the earlier parts fitted easily in my head,

That's standard. Indeed, in my courses I encourage this a bit
for the know-it-alls so that they __fail__ around this point.
Nothing like struggling when your colleagues who you thought
weren't up to snuff are doing it in no time :-)

Keep at it -- Matthias

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