Regex does not match url with www -

Regex does not match url with www -

i'm trying write regex can match both next lines:

http://ficsgames.org/cgi-bin/show.cgi?id=364189186;action=save http://www.ficsgames.org/cgi-bin/show.cgi?id=364189186;action=save

i've got this:

http:\/\/(www)?ficsgames\.org\/cgi-bin\/show\.cgi\?id=[0-9]+;action=save

but doesn't seem work - http://regex101.com/r/vb2cm3/1

you missing dot . within of optional group.

(www\.)?

regex url