Re^3: the case where regex seems to work slower

Hey, it worked for the test case you gave :)

(grumble, grumble, inadequate test cases :( Even these test cases are inadequate, can you figure out why? )

#!/usr/bin/perl

# http://perlmonks.org/?node_id=1196089

use strict;
use warnings;

$\ = $/;

while(<DATA>)
  {
  chomp;
  my $dict = $_;

  $_ = <DATA>;

  my($head, $tail) = map length( $_ // '' ), split /\*/;

  s/\?/[$dict]/g;
  s/\*/ [^$dict ]* /;

  my $qr = qr/^$_/;

  $_ = <DATA>,
    $head <= length($_) && substr($_, $head, 0, ' '),
    $tail && $tail <= length($_) && substr($_, -$tail, 0, ' '),
    print $_ =~ $qr ? "YES" : "NO"
      for 1 .. <DATA>;
  }

__DATA__
ab
a?a
3
aaa
aab
aaac
ab
*a?a
3
aaa
aab
caaa
ab
a?a*
3
aaa
aab
aaac
b
aaaaaaaaaaaaaaaaaaaaaaa*aaaaaaaaaaaaaaaaaa
1
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
b
aaaaaaaaaaaaaaaaaaaaaaa*aaaaaaaaaaaaaaaaaa
1
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
b
*aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
1
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
b
*aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
1
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
b
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa*
1
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
b
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa*
1
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
b
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
1
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
b
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
1
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
[download]

Comment on Re^3: the case where regex seems to work slower Download Code

Replies are listed 'Best First'.
Re^4: the case where regex seems to work slower by rsFalse (Chaplain) on Jul 27, 2017 at 12:57 UTC
Sorry, I didn't understand your second sentence, because parentheses were not balanced ;) Thank you for improvement to cope with other cases. I've submitted, and it took only 171 ms at worst TC, this is #93 - http://codeforces.com/contest/832/submission/28930515 Upd.: In this solution there single spaces in regex are used. They were mysterious for me in previous code, and should be taken by negate character class.	[reply]
Re^5: the case where regex seems to work slower by tybalt89 (Monsignor) on Jul 27, 2017 at 13:37 UTC
The spaces are there to split the target string into three parts, before the '', the star part, and after the star. This prevents trying to match with a pattern equivalent to /aa*/ which causes the long matching time you were seeing;	[reply]