perllongest-prefix

Perl: best way to do longest prefix match (string)

I have a list of around 5000 words. I want to find the longest prefix match among those words for a given word. For example, in my list I have :

1
121
12234
20345
21345

Now If I search for 12134 the result will be 121 (longest match). I know it can be done in different ways. But, what should be the most efficient way ?

Solution 
  • #!/usr/bin/env perl

use strict;
use warnings;

my @prefixes = qw(
    1
    121
    12234
    20345
    21345
);

my $num = '12134';

my ($longest) = sort { length $b <=> length $a } grep { 0 == index $num, $_ } @prefixes;

print "$longest\n";

    Outputs

    121