If you look at the algorithm competition schedule you will see that 600 out of 2000 (the maximum number of participants per qualifications round) advances to the semifinals. My final position is 306 so I believe I advanced to semifinals but I didn’t received yet an official communication from TopCoder.
The match has been intense but it has started in a very bad way. First, I opened the easy problem and I spent 15 minutes to find a solution. I couldn’t come up with a solution. I was shocked because this is usually simple and I always had a first quick solution to it. I decided to move to the medium problem and the same happened. In that case, the text of the problem was too long and I hate this kind of problems so I decided to move on the hard problem. At that point, my hope was almost null because I never been able to solve a TopCoder hard problem. I focused all my remaining time to solve the hard problem and I submitted a solution and I got 448.50 points. I was happy because I knew that I discovered some subtle edge cases and I addressed them but I wasn’t 100% sure that my code was fully functional (never I am).
Then the challenge phase. Only three people (included me) in the room (usually 20 people) did the hard problem. Three tentative to break my code has been done with a negative result (each person lost 25 points for this). I challenged the code of a guy that submitted a solution to the hard problem but without covering an edge case and I got 50 points. So my score became 494.80.
Then the system test. The system test is terrible because if only a single test case against a solution does not pass you automatically get a score of 0. Fortunately my code passed the system test.
I would like to share the problem and my code with you but unfortunately for copyright issues I can’t. You have to register on TopCoder to have access to all the problems.
However, I can share with you my public profile information.
My total topcoder score in the algorithm category (a kind of average of all the competition you did) is now 1167. As you can see, my last match has been significantly better than the previous. Solving the hard problem is a great achievement for me.
Competing on TopCoder is amazing and I like the adrenaline released during the competition. I strongly recommend the experience to any programmers. It doesn’t matter what will be your score, what it matters is challenging yourself, improving yourself and having fun.