Physics olympiad book suggestion

[pcm]

i am in class 11 and have recently completed my mechanics and thermodynamics.
i want to participate in physics olympiad .i used resnick halliday ,irodov problems and iitjee related books.but the problems that come up at olympiads are typically harder than the problems in those books.
so is there any book for problems that would be helpful for me.

 

[Dadface]

i am in class 11 and have recently completed my mechanics and thermodynamics.
i want to participate in physics olympiad .i used resnick halliday ,irodov problems and iitjee related books.but the problems that come up at olympiads are typically harder than the problems in those books.
so is there any book for problems that would be helpful for me.

Google for past olympiad papers.I think they are freely available,both the UK and US versions.