Conversation

Andy Matuschak

@andy_matuschak

SICP 1.2.2 asks for iterative-process impl of change-counting algorithm.

@bryanjclark

+ I tried during

@understudyapp

today—no dice. Ideas?

4:37 AM · Jul 25, 2015Tweetbot for Mac

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@andy_matuschak

@bryanjclark

@understudyapp

just like Fibonacci seq only depends on last 2 vals, change-counting seq depends on last 25

so a straightforward way to extend Fib technique would be to have an at-most-25 elem list accum

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So no lists means no stacks. Interesting.

So lists may not have been introduced but one could argue that someone could discover Church encodings.

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It’s a stretch to say the least!

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I suspect you’re correct, unfortunately.

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@chrisncopeland

I can’t remember, does (define …) return a lambda?

@chrisncopeland

I mean, we know Church figured this out once, maybe Church is the standard for MIT freshmen?

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@chrisncopeland

I concede.