things you need to keep in mind while solving problems.
- they check your efficiency not your language knowlegde.
- they run your programs at extreme cases.
- finally you need a gud algorithm and proper implimentation.
mostly problems are based on number theory, string matching, sorting, graph and others but the input range and time limit makes it harder to solve.
if you want to start with some easier ones then go to my profile. i usually solve easier first [:)].
thats enuf for today next time i will tell you explanation to few problems so you can solve them quite easily.