I think I have precision problems, please inspect my code (CSharp) and give some hints:

UPD: ok, I found some mistakes in my algorithm.

Edited by author 08.01.2013 14:49

OK, I got AC, but I have question to admins:
Is there test with n = 1000, m = 1000? My solution on my PC works more than 0.5 secs with such test.

try to solve this with dp.
my solution with dp( O(n*m) ) works on my pc only  0m0.016s if n=m=1000 :)