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Re: Regular expression problem

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On Mon, Mar 11, 2013 at 4:59 AM, Chris Angelico <rosuav@gmail.com> wrote:
> On Mon, Mar 11, 2013 at 4:42 AM, mukesh tiwari
> <mukeshtiwari.iiitm@gmail.com> wrote:
>> I am trying to solve this problem[1] using regular expression. I wrote this code but I am getting time limit exceed. Could some one please tell me how to make this code run faster.
>
> What is the time limit? I just tried it (Python 2.6 under Windows) and
> it finished in a humanly-immeasurable amount of time. Are you sure
> that STDIN (eg raw_input()) is where your test data is coming from?

Oops, reading comprehension fail. Time limit is 3s on a Pentium III.
I've no idea how long your code will take on that hardware, but I
doubt that it's taking three seconds. So my query regarding source of
test data still stands. Can you put together an uber-simple test
program that just echoes the lines of input, to make sure it really is
coming off stdin?

The problem description certainly does seem to imply stdin, but I
can't see why your code would take three seconds unless it's stalling
for some reason. Though perhaps on a P3 with the maximum 100 tests,
maybe that could take a while...

Something to try: Since you're using re.search(), see if you can drop
the complemented sets at the beginning [^~!@#$%^&*()<>?,.]* and end
[^~!@#$%^&*()<>?,.a-zA-Z0-9]* - they're going to be slow to process.
Also, you can simplify this:

[a-zA-Z0-9][a-zA-Z0-9._][a-zA-Z0-9._][a-zA-Z0-9._][a-zA-Z0-9._][a-zA-Z0-9._]*

to this:

[a-zA-Z0-9][a-zA-Z0-9._]{4,}

The brace notation means "at least 4, at most infinity".

Try those out and see if you still get the results you want.

ChrisA

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Thread

Regular expression problem mukesh tiwari <mukeshtiwari.iiitm@gmail.com> - 2013-03-10 10:42 -0700
  Re: Regular expression problem Chris Angelico <rosuav@gmail.com> - 2013-03-11 04:59 +1100
    Re: Regular expression problem mukesh tiwari <mukeshtiwari.iiitm@gmail.com> - 2013-03-10 11:05 -0700
    Re: Regular expression problem mukesh tiwari <mukeshtiwari.iiitm@gmail.com> - 2013-03-10 11:05 -0700
  Re: Regular expression problem Chris Angelico <rosuav@gmail.com> - 2013-03-11 05:08 +1100
    Re: Regular expression problem mukesh tiwari <mukeshtiwari.iiitm@gmail.com> - 2013-03-10 11:48 -0700
      Re: Regular expression problem Chris Angelico <rosuav@gmail.com> - 2013-03-11 05:57 +1100
    Re: Regular expression problem mukesh tiwari <mukeshtiwari.iiitm@gmail.com> - 2013-03-10 11:48 -0700
  Re: Regular expression problem Terry Reedy <tjreedy@udel.edu> - 2013-03-10 22:06 -0400
    Re: Regular expression problem jmfauth <wxjmfauth@gmail.com> - 2013-03-11 02:28 -0700
      Re: Regular expression problem Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-03-11 10:19 +0000
      Re: Regular expression problem rusi <rustompmody@gmail.com> - 2013-03-11 06:18 -0700
      On topic, please [Was:Re: Regular expression problem] Ned Deily <nad@acm.org> - 2013-03-11 11:13 -0700
  Re: Regular expression problem Serhiy Storchaka <storchaka@gmail.com> - 2013-03-11 20:30 +0200
  Re: Regular expression problem Terry Reedy <tjreedy@udel.edu> - 2013-03-11 16:23 -0400

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