CueUp/greplin Level 3 - Subset Sums

gistfile1.txt

use strict;
use warnings;

use Math::Combinatorics;

my @numbers = (3, 4, 9, 14, 15, 19, 28, 37, 47, 50, 54, 56, 59, 61, 70, 73, 78, 81, 92, 95, 97, 99);
my $total = 0;

for (my $sum = 0; $sum < scalar @numbers; $sum++) {
  next if ($sum < 3);

  my @leftArray;
  for (my $i = 0; $i < $sum; $i++) {
    push @leftArray, $numbers[$i];
  }

  for (my $subsetSize = 2; $subsetSize < $sum; $subsetSize++) {
    my @subsets = combine($subsetSize, @leftArray);
  
    foreach my $subset (@subsets) {
      my $sumVal = eval join '+', @$subset;
      if ($sumVal == $numbers[$sum]) {
        print join(' + ', @$subset), " = ", $numbers[$sum], "\n";
        $total++;
      }
    }
  }
}

print $total, "\n";