Matt Owen

source code for "files/pe/pe_026.pl"

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  1.  #!/usr/bin/perl
  2.  
  3.  sub div_1 {
  4.   my $d = shift;
  5.   my $n = 1;
  6.   my $k = 0;
  7.   my $m = 1;
  8.   my $iter = 0;
  9.   my %hash;
  10.  
  11.   my $last_digit;
  12.  
  13.   my ($digit, $remainder);
  14.  
  15.   $remainder = 1;
  16.   while ($remainder) {
  17.   $k = 0;
  18.  
  19.   while (10**$k*$n < $d) {
  20.   $k++;
  21.   }
  22.  
  23.   $m = 10**$k*$n;
  24.  
  25.   $last_digit = int 10**$k*$n / $d;
  26.   $remainder = 10**$k*$n % $d;
  27.   $digit .= ('0' x $k) . $last_digit;
  28.  
  29.   if (defined $hash{"$last_digit $remainder"}) {
  30.   return $iter - $hash{"$last_digit $remainder"};
  31.   }
  32.   else {
  33.   $hash{"$last_digit $remainder"} = $iter;
  34.   }
  35.  
  36.   $n = 10**$k*$n - $last_digit*$d;
  37.   $n *= 10;
  38.   $iter++;
  39.   }
  40.  
  41.   return 0;
  42.  }
  43.  my ($largest, $length, $d);
  44.  $largest = 0;
  45.  
  46.  for (2..1000) {
  47.   $length = div_1($_);
  48.   if ($largest < $length) {
  49.   $largest = $length;
  50.   $d = $_;
  51.  
  52.   }
  53.  }
  54.  
  55.  print "1/$d with length=$largest";
  56.  #print $d, '!!';