Re: [FWP] longest substring with unique characters

[abigail@foad.org]

On Fri, Jan 19, 2001 at 03:34:24PM +0100, Julien Quint wrote:
> #!/usr/bin/perl -w
> 
> use strict;
> 
> while (<>) {
>    chomp;
>    my $longest = "";
>    while (/./g) {
>      my $match = $&;
>      my $substr = $';
>      ($match, $substr) = ($match . $&, $') while $substr =~ /^[^$match]/;
>      $longest = $match if length($match) > length($longest);
>    }
>    print "$longest\n";
> }
> 
> __END__
> 
> I guess this version is more perlish.


There's no need to disassemble the string yourself, one regex will do:

#!/opt/perl/bin/perl -w
 
use strict;
 
my $max = 0; $_ = shift;
while (/\G(.)(?=((?:(?!\1).)*))/g) {$max = $1.$2 if length $max < length $1.$2}
print $max, "\n";

__END__

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