use strict;
use Math::monthly::CarClumps qw\count\;

my ( @order , @clumps,
     $total , @speeds );

        # speed of cars
@speeds = ( 50 .. 59 );
        # initialize @clumps as {0}
@clumps = (0) x ( @speeds + 1 );

clumps ( @speeds );

foreach my $i ( 1 .. $#clumps )
  { print $i + $speeds[0] - 1, " :\t$clumps[$i]\t( ",
      ( $clumps[$i] * 100 / $total ), "% )\n" }
print "total :\t$total ( = ", scalar @speeds, "! )\n";

exit 0;

sub clumps {
  my @cars  = @_;
  if ( scalar @cars eq 0 )
    { $clumps[count(@order)]++; $total++ }
  else
    { foreach ( 0 .. $#cars)
        { my $speed = pop @cars;
          unshift @order, $speed;
          clumps( @cars );
          unshift @cars, $speed;
         }
    }
  shift @order;
  return 0;
}