use strict;
use warnings;

find(100, [], [100, 50, 20, 10, 5, 2, 1]);

sub find {
    my $left = $_[0];
    my @set = @{$_[1]};
    my ($denom, @denom) = @{$_[2]};

    print join(', ', map { "($_->[1] $_->[0]'s)" } @set), "\n" if !$left;
    return if !$left || !$denom;

    find($left, [@set], [@denom]);
    for (1..($left / $denom)) {
        find(($left - $denom * $_), [@set, [$denom, $_]], [@denom]);
    }    
}