test_perl_5.pl

#!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper;

my @sequenze;

for my $a1 (0 .. 2) {
        for my $a2 (0 .. 2) {
                for my $a3 (0 .. 2) {
                        for my $a4 (0 .. 2) {
                                for my $a5 (0 .. 2) {
                                        for my $a6 (0 .. 2) {
                                                for my $a7 (0 .. 2) {
                                                        for my $a8 (0 .. 2) {
                                                                my $seq = [ $a1, $a2, $a3, $a4, $a5, $a6, $a7, $a8 ];
                                                                push @sequenze, $seq;
                                                        }
                                                }
                                        }
                                }
                        }
                }
        }
}

my @sequenze2;

for my $seq (@sequenze) {
        my @seq2 = (1);

        for my $i (0 .. 7) {
                next_elem( $i, \@seq2, $seq);
        }

        my @seq3 = @seq2;

        my $tot = shift @seq2;

        while (my $elem = shift @seq2) {
                if ($elem eq '+') {
                        $tot += shift @seq2;
                } elsif ($elem eq '-') {
                        $tot -= shift @seq2;
                } else {
                        print 'ERRORE ';
                }
        }

        next unless $tot == 100;

        push @seq3, '=', $tot;
        my $buf = join '', @seq3;
        print $buf, "\n";
}


sub next_elem
{
        my ($i, $seq2, $seq) = @_;

        my $nextnum = $i+2;
        my $concat;

        if ($seq->[$i] == 0) {
                push @$seq2, '+';
        } elsif ($seq->[$i] == 1) {
                push @$seq2, '-';
        } else {
                $concat = 1;
        }

        if ($concat) {
                my $num = pop @$seq2;
                $num = $num*10 + $nextnum;
                push @$seq2, $num;
        } else {
                push @$seq2, $nextnum;
        }

}