perl -le"%h=(), undef @h{split'',$_}, keys %h == 3 and print for '0000
+'..'9999'"
[download]

BrowserUk,


Thank you for this.

This is the message I got:

syntax error at ns.pl line 1, near "-le"
Execution of ns.pl aborted due to compilation errors.
[download]

?

The solution I posted is a one-line perl command, to be run from a command shell prompt, not to be embedded within a perl source file.

If you're running under *nix, then you'll have to exchange the quotes like so:

perl -le'%h=(), undef @h{split"",$_}, keys %h == 3 and print for "0000
+".."9999"'
[download]

The following will run as a script:

#!/usr/bin/perl -lw
use strict;

for ( '0000'..'9999' ) {
    my %h;
    undef @h{split'',$_};
    keys %h == 3 and print;
}
[download]

---

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

"I'd rather go naked than blow up my ass"

perldoc perlrun

$ perl -MO=Deparse   -le"%h=(), undef @h{split'',$_}, keys %h == 3 and
+ print for '0000'..'9999'"
BEGIN { $/ = "\n"; $\ = "\n"; }
;
(%h) = (), undef @h{split(//, $_, 0)}, keys %h == 3 and print $_ forea
+ch ('0000' .. '9999');
-e syntax OK
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$ indicates a command prompt (a shell, like bash/csh/cmd...)

This version directly generates the list of desired patterns rather than filtering through all 4-digit patterns, just to demonstrate another approach. It also works for any length of digit string.

#/usr/bin/perl -w
use strict;
use Algorithm::Loops qw< NestedLoops NextPermute >;
my( $uniq )= ( @ARGV, 3 ); # 3 unique digits plus one duplicate digit
my $digs= NestedLoops(
    [ [0..9], ( sub { [1+$_..9] } ) x ($uniq-1) ],
);
my @digs;
while(  @digs= $digs->()  ) {
    do {
        for my $dup (  0 .. $#digs  ) {
            for my $after (  $dup .. $#digs  ) {
                my @result= @digs;
                splice @result, 1+$after, 0, $digs[$dup];
                print @result, $/;
            }
        }
    } while(  NextPermute( @digs )  );
}
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Tye,

Thank you, I will look into this one.

Cheers,

M.ROMAN

You can try the following algorithm:

1. pass through your input one digit per time
2. use a hash to count how often each digit occurs
3. once you are finished, pass through the hash (again) to see how many digits are ocuring two times
4. print yes/no

Once you have done this, think how to adapt the algorithm to handle the special case 1111....

Have Fun! Rata

PS.: it is good that you looked for an old thread! However you'll get more answers if you'd opened a new thread and just had provided a link to the old one! well, next time ;-)

Ratazong,

Thank you for your reply.

(vigorously flapping noob wings)

Argh! Can't fly that high as of yet . . .

I will link to a thread instead next time however :)


Cheers,

M.Roman