sub parse_datetime($)
{
 $_ =~ /(\d\d\d\d)-(\d\d)-(\d\d) (\d\d):(\d\d)/;
 return($1, $2, $3, $4, $5);
}
[download]

You're not using the argument you pass to parse_datetime, but $_, which is a global variable.

Try

sub parse_datetime($)
{
 my $s = shift;
 $s =~ /(\d\d\d\d)-(\d\d)-(\d\d) (\d\d):(\d\d)/;
 return($1, $2, $3, $4, $5);
}
[download]