http://paperlined.org/dev/src/pl/kenken/iterate.pl

#!/usr/bin/perl

# <short description of program>

    use strict;
    use warnings;

    use Data::Dumper;
    use List::Util qw[reduce max min];

    my $num_cells = 3;
    my $result = 8;
    my $operation = 'add';
            # ^ first three letters
            # ^ first letter:   (A)dd  (S)ub  (D)iv  (M)ul

    my $max_val = 6;




$operation = 'sub' if ($operation eq 'min');        # 'min'us => 'sub'tract

my @cells = 1..$num_cells;

# iterate through all possible cell values
my %union;
my $total_iter = $max_val ** $num_cells;
for (my $ctr=0; $ctr<$total_iter; $ctr++) {
    my $dist = $ctr;
    my $last = 0;
    for (my $pos=0; $pos<$num_cells; $pos++) {
        $cells[$pos] = ($dist % $max_val) + 1;
        if ($cells[$pos] < $last) {
            $last = -1;
            last;
        }
        $last = $cells[$pos];
        $dist = int($dist / $max_val);
    }
    #next if (($operation eq 'add' || $operation eq 'mul') && $last == -1);     # skip this sequence if it's out of order
    next if ($last == -1);     # skip this sequence if it's out of order

    do_operation(@cells);
}

print "\n\nyes:  ", join(" ", sort {$a <=> $b} keys %union), "\n";
print "no:   ", join(" ", grep {!$union{$_}} 1..$max_val), "\n";

sub do_operation {
    my $r = 0;
    if ($operation eq 'add') {
        $r = reduce {$a + $b} @_;
    } elsif ($operation eq 'sub') {
        $r = max(@_) - min(@_);     # due to commutivity, there can only be two operands
    } elsif ($operation eq 'mul') {
        $r = reduce {$a * $b} @_;
    } elsif ($operation eq 'div') {
        $r = max(@_) / min(@_);     # due to commutivity, there can only be two operands
    }

    if ($r == $result) {
        print join(" ", @_), "\n";

        foreach my $u (@_) {
            $union{$u}++;
        }
    }
}