A somewhat non-standard approach, just for the fun of it:

my @a = qw( fred bob joe jim mary elaine );
my @b = qw( frank joe jim mary bob );

my $str = join(" ", @a) . "&" . join(" ", @b);

if ($str =~ /(?:\b\w+\b\s*)+?
             ((?:\b\w+\b\s*)+)
             (?:\s*\b\w+\b\s*)+?
             &
             (?:\b\w+\b\s*)+?
             \1
             (?:\s*\b\w+\b)+?/x) {
    my $result = $1;
    $result =~ s/\s*$//;
    print "found '$result'\n";
}

[download]

Note: it works on the example given, I didn't test it extensively.

Just my 2 cents, -gjb-

In reply to Re: Finding largest common subset in lists? by gjb
in thread Finding largest common subset in lists? by anjiro

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