Sometimes verbose code is faster. This beat out the above regexp examples in all the cases I threw at it. (NOTE: the "Note unique" example is a best case scenario for this example, but the worst case of "All unique" still performs better").
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 $digits !~ /(.).*\1/;
},
u9 => sub {
return 0 if index($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__
All unique (2491306578):
Rate u1 u2 u3 u4 u9
u1 14387/s -- -71% -91% -91% -93%
u2 50142/s 249% -- -67% -67% -74%
u3 153182/s 965% 205% -- -0% -22%
u4 153395/s 966% 206% 0% -- -22%
u9 195811/s 1261% 291% 28% 28% --
Not unique (1102345678):
Rate u1 u2 u3 u4 u9
u1 14381/s -- -71% -97% -97% -99%
u2 50429/s 251% -- -91% -91% -97%
u3 531431/s 3595% 954% -- -4% -65%
u4 556425/s 3769% 1003% 5% -- -64%
u9 1539566/s 10606% 2953% 190% 177% --