This is the 100% way for Green Day's Warning, I'm sure of it, I saw them live, TWICE and I've taken pics (sshh!) ANd it's correct, it may not sound correct because of the bass and stuff that's because the bass is the main thing here!
These are the only chords used:
Cadd9 (032033) OR (032030)
D     (000233) OR (000230)
G     (320033) OR (320030)

Intro, Verse and Chorus:
Cadd9 x4     D x4     G x4     Dx4
Bridge:
Bass does it all, Guitar doesn't do anything, unless the guitarist has effects, use delay and strum 6th string G.
And that's it, If you don't believe me, go see Green Day Live and watch closely, I bet you $400 bux I'm right!