The problem *can* be translated into a LCSS thing, just by reformatting the numbers into a hexdump of appropriate size:

_{Addendum: added display of alingnment positions pa/pb}

 ...
 use String::LCSS_XS qw(lcss);
  
 my $str_a =  join '', map sprintf("%08x", $_), 1,2,3,6,7,9,1,-7,2,6;
 my $str_b =  join '', map sprintf("%08x", $_), 7,6,7,9,12,-22,-3;

 # - - - - - - - - - - - - - - - - - - - #
 my @longest = lcss( $str_a, $str_b );
 # - - - - - - - - - - - - - - - - - - - #
 print join ',', map hex, $longest[0] =~ /.{8}/g;

 my ($pa, $pb) = map 1+$_/8, @longest[1,2];
 print "\na's pos # $pa alingns to b's pos # $pb\n";
 ...
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This will show:

 6,7,9
 a's pos # 4 'aligns' to b's pos # 2
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... but its hard to say without knowing what you are really trying to do. This might be very very inefficient and rather suboptimal.

Regards

mwa

use strict;

use Algorithm::LCSS qw( LCSS );
use Data::Dump qw /dump/;

my @first_sequence  = (1,2,3,6,7,9,1,-7,2,6);
my @second_sequence = (7,6,7,9,12,-22,-3);

my $lcss_ary_ref = LCSS( \@first_sequence, \@second_sequence );

{local $" = ','; print "The aligned sequence is @$lcss_ary_ref\n";}
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generosity killed the cat (false buddha)

#!/usr/bin/perl 
use strict;
use warnings;
use Data::Dumper;
use List::Compare;

my $a = '1,2,3,6,7,9,1,-7,2,6';
my $b = '7,6,7,9,12,-22,-3';
my @a = split ',', $a; 
my @b = split ',', $b; 

my $lc = List::Compare->new( \@a, \@b );

my @intersection = $lc->get_intersection;

print Dumper(@intersection);
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output :

$VAR1 = '6';
$VAR2 = '7';
$VAR3 = '9';
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voilą ;)
PooLPi

From the example it seems that you are searching the Longest Common Subsequence