Basically, it's just

C Em-F
Am Em-F

throughout the song. If you want to simplify it, you can change it to 
C Em 
Am F

I hope this makes sense! Good luck :) Mess around with it

C (x32010@1)    Em (022000@1)      F(ohh) (133211@1)two zero one two (ohh)
      Am (x02210@1)    Em-F
it's alright oh it's alright

Cyou (x32010@1)know what they say
Em (022000@1)              Flife (133211@1)aint always easy
     Am (x02210@1)         Em-F
and everyday were survivors
    Cso (x32010@1)forget the day
Em (022000@1)             F (133211@1)          Amits (x02210@1)all about tonight at the school
             Em (022000@1)        Fand (133211@1)start a riot a-riot, be a rebel

C (x32010@1)                  Em (022000@1)       Fbottles (133211@1)popping till we cant stand
Am (x02210@1)                     Em-F
you keep it rocking till 6 am
C (x32010@1)                     Em (022000@1)  Fnew (133211@1)york to london over to japan
        Am (x02210@1)                   Emturn (022000@1)it up turn it up mash it up
          Fwe (133211@1)gunna party like
C (x32010@1)                       Em (022000@1)        Fparty (133211@1)like, likes its the end of the world
          Am (x02210@1)                Em-F
we gonna party like, like its 2012
              Cyou (x32010@1)know that it doesn't matter
           Em (022000@1)          Fas (133211@1)long as we got each other
        Am (x02210@1)                   Em-
turn it up turn it up mash it up
 F (133211@1)                      C (x32010@1)  Em-F
it aint the end of the world (ohh)
          Am (x02210@1)            Em (022000@1)          Fwe (133211@1)gunna live like its the end of the world
C (x32010@1)               Em-F
gunna party like(ohh)
        Am (x02210@1)                  Em-
turn it up turn it up mash it up
 F (133211@1)                       Cit (x32010@1)aint the end of the world