It is really an easy contest. The 250 and 500 are easy problems that can be solved straightforwardly. The 1000pt problem is an greedy that takes a little thought and I managed to solve it in just 11 mins, which made me to the top 20 coders that night. 
During the challenge phase, I gained just 50 pt with only one successful challenge. At last, I got 1555pt and gained 112 points for that nice preformance and made my rating to 1554 and got it yellow!
