#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11123870
use warnings;
use List::Util qw( uniq );

print "$_\n" for find( 100, '1 99 2 40 50 60 90 3 5 95 100' );
print "\n";
print "$_\n" for find( 100, '5 5 5 5 10 15 80 99' );

sub find
  {
  my ($target, $from, $have) = @_;
  $have //= '';
  $target == 0 and return $have =~ s/.//r;
  $target > 0 && $from =~ s/\d+// or return ();
  uniq find( $target - $&, $from, "$have+$&"), find(  $target, $from, $have );
  }