use Benchmark qw( cmpthese ) ; my $digits = 2491306578; cmpthese( -5, { u1 => sub{ for ( 0 .. 9 ) { return 0 if $digits !~ /$_/;} return 1; }, u2 => sub{ my @x = sort split //, $digits; my $x = join "", @x; $x =~ tr/0-9//s; length $x == 10 ? return 1 : return 0; }, u3 => sub { return 0 if $digits =~ /(\d).*\1/; return 1; }, u4 => sub { return $digits !~ /(.).*\1/; }, u5 => sub { return $digits =~ /^(?=.*?0)(?=.*?1)(?=.*?2)(?=.*?3)(?=.*?4)(?=.*?5)(?=.*?6)(?=.*?7)(?=.*?8)(?=.*?9)/; }, u6 => sub { return 0 unless $digits =~ y/0/0/; return 0 unless $digits =~ y/1/1/; return 0 unless $digits =~ y/2/2/; return 0 unless $digits =~ y/3/3/; return 0 unless $digits =~ y/4/4/; return 0 unless $digits =~ y/5/5/; return 0 unless $digits =~ y/6/6/; return 0 unless $digits =~ y/7/7/; return 0 unless $digits =~ y/8/8/; return 0 unless $digits =~ y/9/9/; return 1; }, u9 => sub { return 0 if index($digits, substr($digits,0,1), 1) != -1; return 0 if index($digits, substr($digits,1,1), 2) != -1; return 0 if index($digits, substr($digits,2,1), 3) != -1; return 0 if index($digits, substr($digits,3,1), 4) != -1; return 0 if index($digits, substr($digits,4,1), 5) != -1; return 0 if index($digits, substr($digits,5,1), 6) != -1; return 0 if index($digits, substr($digits,6,1), 7) != -1; return 0 if index($digits, substr($digits,7,1), 8) != -1; return 0 if index($digits, substr($digits,8,1), 9) != -1; return 1; }, } ); __END__ #### Rate u1 u2 u9 u4 u3 u6 u5 u1 10982/s -- -72% -95% -95% -95% -96% -97% u2 39808/s 262% -- -83% -83% -83% -85% -90% u9 229374/s 1989% 476% -- -4% -4% -12% -42% u4 238244/s 2069% 498% 4% -- -1% -9% -40% u3 240061/s 2086% 503% 5% 1% -- -8% -39% u6 261581/s 2282% 557% 14% 10% 9% -- -34% u5 394564/s 3493% 891% 72% 66% 64% 51% --