This has Vietnamese version. Please go to mo2000.html

APMO 2000
I've just joined in the 13th APMO (8/3/2000 in Vietnam). I think I had a half correct. Here're the 5 problems, must be done in 4 hours:

Now I think there's no matter with the first 4 problems, each of them can be explained in a few lines. But the most difficult is problem 5, and the solution I know is long.

VMO 2000
The 38th VMO 1999-2000 was held in March, 13 and 14. There're 3 hours for 3 problems each day. And this is the 6 problems:

Now I still don't know how to solve P2.2 and P3. If anyone know, please send it so me. Thank you!