topcoder

I registered with topcoder this weekend. It might be fun to keep my wits sharp with the occasional algorithm competition. I tried one of the practice problems. I like Java more than the other languages to solve the problem. The problem didn't seem to demand object orientation so I ended up using static methods. This was a problem (An illegal access exception occurred. Make sure your method is declared to be public) when I tried to submit my work back into their system since they seem to instantiate your class and then call your method to test. I think I found a bug or at least in inconsistency with the question. I reported it so we'll see. Also, I looked over the problem and didn't come back to it until the next day. This probably made it take too long and I think that's why I only got ~90 points. My solution seemed to work for all of their cases. Better luck next time.

Update: Topcoder acknowledged the bug in the 300pt 1-SRM 144 Div 1 problem. The statement considers example "123210122", so the second line you quote should look like

Because Q[0] = P[0] + P[1] = 1 + P[1] = 1 (!!), we know that P[1] = 0.

instead of

Because Q[0] = P[0] + P[1] = 1 + P[1] = 0, we know that P[1] = 0.