my @first = ((1..200), qw(a b c d e f)) ;
my @second= ((1..200), qw(b a c d e f)) ;

Benchmark: timing 2000 iterations of DComp, faq, grep...
DComp: 12 wallclock secs (11.52 usr + 0.00 sys = 11.52 CPU)
  faq:  2 wallclock secs ( 1.48 usr + 0.00 sys =  1.48 CPU)
 grep:  1 wallclock secs ( 1.35 usr + 0.00 sys =  1.35 CPU)