De Bruijn sequences: Difference between revisions
Added Perl example
SqrtNegInf (talk | contribs) (Added Perl example) |
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PIN number 8145 missing
</pre>
=={{header|Perl}}==
{{trans|Perl 6}}
<lang perl>use strict;
use warnings;
use feature 'say';
my $seq;
for my $x (0..99) {
my $a = sprintf '%02d', $x;
next if substr($a,1,1) < substr($a,0,1);
$seq .= (substr($a,0,1) == substr($a,1,1)) ? substr($a,0,1) : $a;
for ($a+1 .. 99) {
next if substr(sprintf('%02d', $_), 1,1) <= substr($a,0,1);
$seq .= sprintf "%s%02d", $a, $_;
}
}
$seq .= '000';
sub check {
my($seq) = @_;
my %chk;
for (0.. -1 + length $seq) { $chk{substr($seq, $_, 4)}++ }
say 'Missing: ' . join ' ', grep { ! $chk{ sprintf('%04d',$_) } } 0..9999;
say 'Extra: ' . join ' ', sort grep { $chk{$_} > 1 } keys %chk;
}
my $n = 130;
say "de Bruijn sequence length: " . length $seq;
say "\nFirst $n characters:\n" . substr($seq, 0, $n );
say "\nLast $n characters:\n" . substr($seq, -$n, $n);
say "\nIncorrect 4 digit PINs in this sequence:";
check $seq;
say "\nIncorrect 4 digit PINs in the reversed sequence:";
check(reverse $seq);
say "\nReplacing the 4444th digit, '@{[substr($seq,4443,1)]}', with '5'";
substr $seq, 4443, 1, 5;
say "Incorrect 4 digit PINs in the revised sequence:";
check $seq;</lang>
{{out}}
<pre>de Bruijn sequence length: 10003
First 130 characters:
0000100020003000400050006000700080009001100120013001400150016001700180019002100220023002400250026002700280029003100320033003400350
Last 130 characters:
6898689969697769786979698769886989699769986999777787779778877897798779978787978887889789878997979887989799879998888988998989999000
Incorrect 4 digit PINs in this sequence:
Missing:
Extra:
Incorrect 4 digit PINs in the reversed sequence:
Missing:
Extra:
Replacing the 4444th digit, '4', with '5'
Incorrect 4 digit PINs in the revised sequence:
Missing: 1459 4591 5814 8145
Extra: 1559 5591 5815 8155</pre>
=={{header|Perl 6}}==
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