First creative solution for Restricted Prime by coells - python coding challenges

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First solution in Creative category for Restricted Prime by coells

# lame
checkio = lambda n: all(i==n or pow(i,n+~False,n)==True for i in map('   , . "'.index,',."'))

April 9, 2014

Comments:

coells on April 9, 2014, 9:02 p.m.
Good news everyone! The very first solution I have no idea why it works... -- Hubert J. Farnsworth

veky on April 10, 2014, 1:53 p.m.
I agree with line 1. :-P

coells on April 10, 2014, 2:01 p.m.
You should rather explain why it works :-P I thought Carmichael number would pass for any witness chosen.

veky on April 10, 2014, 4:19 p.m.
Carmichael numbers are not enough, since you're special-casing 3, 5 and 7. Of course it doesn't really work in general, but it works up to 1e4 (in fact up to 29340:).

coells on April 10, 2014, 5:50 p.m.
Of course! When I was developing the test I had to deal with ~30 pseudoprimes. While I factorized these and got few high factors and forgot only 7 were Carmichael numbers (all divisible by 3,5,7). The chosen bases are enough to violate Carmichael's definition and that's why it works. Thanks!

veky on April 10, 2014, 6:13 p.m.
The problem with communicating with you is that I never know if you're teasing me, or honestly asking something. But I'm glad I could help. :-)

coells on April 10, 2014, 6:22 p.m.
I'm not teasing you at all :-D I mean it. Really. That's just the way I am.

veky on April 10, 2014, 6:26 p.m.
I see it here. But that question from email was just teasing, admit it. :-P

coells on April 10, 2014, 6:34 p.m.
D-: I refuse to testify without my lawyer.

veky on April 10, 2014, 7:23 p.m.
I don't need any further proof. :-PP

coells on April 10, 2014, 7:54 p.m.
To be fair, I also never know if you're laughing to my solution or saying some part is fine ^.^

veky on April 10, 2014, 8:10 p.m.
Yes, but that's a feature you asked for. :-P

Sim0000 on April 19, 2014, 4:48 a.m.
Great! Fermat test with 3, 5, 7.

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