use List::Util qw/first sum/;
use strict;
use warnings 'all';

my @list = (62, 83, 121, 281, 486, 734, 771, 854, 885, 1003);
my $sum = sum(@list)/2;
print "Trying for $sum with possibilities @list\n";
my @match = sum_to($sum, [], \@list);
print @match ? "MATCH @match\n" : "No match\n";

sub sum_to {
        my ( $target, $so_far_ref, $possibilities_ref ) = @_;
        my @so_far = @$so_far_ref;
        my @possibilities = @$possibilities_ref;
        local $_;
        my $exact = first { $_ == $target } @possibilities;
        return $exact if $exact;
        local $_;
        my @indices = grep { $possibilities[$_] <= $target } 0 .. $#po
+ssibilities;
        unless ( @indices ) {
                print "That branch didn't work.\n";
                return;
        }
        my ( $sum, $try, @match );
        INDEX:
        for my $index ( @indices ) {
                my @internal_possibilities = @possibilities;
                my @internal_so_far = @so_far;
                $try = splice @internal_possibilities, $index, 1;
                push @internal_so_far, $try;
                print "Guessed @internal_so_far; recursively trying fo
+r ", $target - $try, " with possibilities @internal_possibilities\n";
                @match = sum_to($target - $try, \@internal_so_far, \@i
+nternal_possibilities) and last INDEX;
        }
        return @match ? ( $try, @match ) : ();
}
[download]