You have a point, though if I were going the verbose route, I would use the transliterate function rather than an index-substr. The back reference method come out slightly faster on my computer than index-substr with transliterate sightly ahead of both. It is moot however, tye's solution above (u5) pretty much spanks all of them.
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% --