Re^2: Speeding permutation counting

BrowserUk,
Once I understood the problem, I came up with a solution very similar to yours. When I logged in this morning, I noticed that you had already came up with the idea. Why does work have to get in the way of fun?

I doubt there would be a speed improvement but I am pretty sure you only have to count '01' since '10' is just a reflection. Additionally, you should only need to calculate ('11' and '00') or ('11' and '10') or ('00' and '10'). The remaining two can be obtained with math.

Cheers - L~R

Comment on Re^2: Speeding permutation counting

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Re^3: Speeding permutation counting by albert (Monk) on Jul 21, 2007 at 23:38 UTC
In my problem '01' is different than '10', and I need to count them separately. Still, your point of not needing to count the last is well taken, as I can count 3, and thereby know the 4th. However, by doing this, I'm not seeing any significant performance gains, and it may be a bit slower. `Rate browser+LR browserUK browser+LR 19055/s -- -2% browserUK 19509/s 2% --` [download] Code for benchmarking... <Reveal this spoiler or all in this thread>	[reply] [d/l] [select]

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Re^3: Speeding permutation counting
by albert (Monk) on Jul 21, 2007 at 23:38 UTC

              Rate browser+LR  browserUK
browser+LR 19055/s         --        -2%
browserUK  19509/s         2%         --
[download]

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