Re: [FWP] Golf (7 strokes is par!)

[Jeff Pinyan <jeffp@crusoe.net>]

On May 1, Jeff Helman said:

>>   if (YOUR CODE HERE) { print "$_ is a power of 2" }
>     if (YOUR CODE HERE) { print "$_ is NOT a power of 2" }
>
>then $_&$_-1 would match your 7.  So I'll bite, what was your 7? (Of
>course, you can send it to me privately if you don't want to spoil it
>quite yet.)

Yes, I am a foolish stupid scum.  My mistake.  You are right with

  $_&$_-1

Do you happen to have the proof for why that is 0 for ONLY powers of 2? :)

-- japhy


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