sub sumTo {
    my $target = shift;
    for my $i ( 0 .. $#_ ) {
        return [ $_[ $i ] ] if $_[ $i ] == $target;
        if( @{
            $_ = sumTo( $target - $_[ $i ], @_[ 0 .. $i-1, $i+1 .. $#_ ] )
        } ) {
            return [ $_[ $i ], @{ $_ } ];
        }
    }
    return [];
}