my @interval_arrays = map [$a[$_], $b[$_]], 0..$#a;

##</code><code>##

my @intersected_arrays = map {
    my $min = $s1 < $_->[0] ? $_->[0] : $s1;
    my $max = $s2 > $_->[1] ? $_->[1] : $s2;
    $min <= $max ? [$min, $max] : ();
} @interval_arrays;