#!/usr/bin/perl
use warnings;
use strict;
use Data::Dumper;
use Benchmark qw/:all/;

sub LCSRegEx {
    my $substr = $_[0];
    my $len = length $_[0];
    my $off = 0;
    while ($substr) {
        my @matches = grep /\Q$substr/, @_;
        last if @matches == @_;
        $off++;
        $len-- and $off=0 if $off+$len > length $_[0];
        $substr = substr $_[0], $off, $len;
    }
    return $substr;
}

sub LCSIndex {
    my $substr = $_[0];
    my $len = length $_[0];
    my $off = 0;
    while ($substr) {
        my @matches = grep { -1 != index $_, $substr } @_;
        last if @matches == @_;
        $off++;
        $len-- and $off=0 if $off+$len > length $_[0];
        $substr = substr $_[0], $off, $len;
    }
    return $substr;
}

my $result = timethese( -5, {
   LCSRegEx => sub {
      for ([ qw(fooabc123 fooabc321 foobca232) ],
           [ qw(abcfoo123 bcafoo321 foo123abc) ],
           [ qw(foo bor boz bzo) ]) {
         LCSRegEx(@{$_});
      }
   },
   LCSIndex => sub {
      for ([ qw(fooabc123 fooabc321 foobca232) ],
           [ qw(abcfoo123 bcafoo321 foo123abc) ],
           [ qw(foo bor boz bzo) ]) {
         LCSIndex(@{$_});
      }
   }
});
cmpthese $result;