After a solid night's sleep I managed to come up with the
following implementation that generates the permutations
in the desired order without a separate sort step:
#!/usr/bin/perl -w
use strict;
# set up the initial 5 arrays into @a
my @a=([0..2],[0..2],[0..2],[0..2],[0..2]);
# build non-zero versions of those arrays
my @nz=map {[grep {$_ != 0} @$_]} @a;
# permute in order....
my @foo;
foreach (15,14,13,11,7,12,10,6,9,5,3,8,4,2,1,0){
push @foo,@{permute('',
($_ & 0x01)?$nz[0]:[0],
($_ & 0x02)?$nz[1]:[0],
$a[2],
($_ & 0x04)?$nz[3]:[0],
($_ & 0x08)?$nz[4]:[0]);}
}
# print out results
print "$_\n" for (@foo);
# permute lists recursively
sub permute{
my ($prefix,$c,@arrays)=@_;
my @ret=();
foreach(@$c){
my $f=$prefix.$_;
if(scalar(@arrays)==0){
push @ret,$f;
}else{
push @ret,@{permute($f,@arrays)};
}
}
return \@ret;
}
