use strict; use warnings; my $zero = shift || 3; my $one = shift || 2; my @array = ( (0) x $zero, (1) x $one ); # print "@array\n"; print join ('', @array), "\n"; while (1) { my $cand = $#array; while ($cand) { if ($array[$cand-1] == 0 and $array[$cand] == 1) { ($array[$cand-1], $array[$cand]) = ($array[$cand], $array[$cand-1]); if ($cand < $#array) { @array[$cand+1..$#array] = sort @array[$cand+1..$#array]; } last; } --$cand; } last unless $cand; # print "@array\n"; print join ('', @array), "\n"; } #### sub iter { my $zero = shift || 3; my $one = shift || 2; my $init = 0; my @array = ( (0) x $zero, (1) x $one ); return sub { $init++ or return join('', @array); my $cand = $#array; while ($cand) { if ($array[$cand-1] == 0 and $array[$cand] == 1) { ($array[$cand-1], $array[$cand]) = ($array[$cand], $array[$cand-1]); if ($cand < $#array) { @array[$cand+1..$#array] = sort @array[$cand+1..$#array]; } last; } --$cand; } return $cand ? join( '', @array) : undef; } } my $i = iter(@ARGV); while (my $str = $i->()) { print "$str\n"; } #### $cand < $#array - 1 and @array[$cand+1..$#array] = reverse @array[$cand+1..$#array];