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Date: Mon, 3 Nov 2014 09:12:56 +1100
Subject: Re: what can i do to improve my skill after finished python course on codecademy
From: Chris Angelico <rosuav@gmail.com>
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On Mon, Nov 3, 2014 at 9:07 AM, Dave Angel <davea@davea.name> wrote:
> Brute force would take a few millenia, as something like
>     ans = sum(range( BIG ) - sum(range(1000))
>
> But just knowing the math lets you simplify it to something like
>    ans = (1000 + BIG) * (BIG - 1000) / 2

Suggestion: Master the brute-force approach first, and use that (on
small ranges) to verify the simplified version. And if you already
happen to know the sum of all numbers from 1 to 100, say, then you can
test both approaches against that, to be sure they're right.

ChrisA