# comparing @merged with @a and @b:
my $pass = 1;
for (my ($ai,$bi,$mi) = (0,0,0); $mi < $#merged; ) {
    ($a[$ai++] eq $merged[$mi++]) or $pass = 0 or last;
    ($b[$bi++] eq $merged[$mi++]) or $pass = 0 or last;
}
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