Finally, I start my career on TopCoder.Com with a not-yet-good JAVA language. My first rating is 1416 (blue), not bad for the first time competitor. Wish a good progress forward for me.

(taken from AsiaOne Business http://office.asiaone.com.sg/mymoney/startout/20070128_005.html)

When Ms Merry Riana stepped into a car showroom in Ubi three years ago, she was just 24 but had her eyes set on her first car - a black Mercedes-Benz E200 costing $180,000.

The car salesman checked her income documents to ensure she qualified for a loan. She certainly did: In the previous year, her first year of work after graduating from university, she earned more than $200,000 as an insurance adviser - a never-say-die one who usually worked seven days a week. When she bought the car, she had just been promoted to the post of manager, training and overseeing six advisers. A lot of Ms Riana’s money is invested in her business to pay for office space, infrastructure and support staff. She has whole-life insurance policiies and unit trusts. In Jakarta, she and her husband have booked a new two-storey terrace house. She subsequently set up her own insurance firm - Merry Riana Organization - in Anson Road and now has more than 40 advisers and support staff. Last month, she received an Outstanding Young Alumni award from her alma mater, Nanyang Technological University (NTU). ‘It’s because of my initial difficulties that I have worked very hard to succeed,’ she says over tea in her office. She has found marital bliss, too. Her husband, Mr Alva Tjenderasa, 26, is a fellow Indonesian who helps her with her business.
(more…)

For someone there, happy birthday, wish a nice age for you, God bless you… Glad to hear your voice last night…

“This was a (so far) unique endeavor for USACO. Richard Peng and I invited several of China’s best competitors and veterans to devise some very ‘evil’ tasks for a very challenging contest.” (http://ace.delos.com/CHN07results).

Wow, extremely challenging and hard problem set of USACO. Say if we can separate 6 problems in IOI as 2 easy - 2 medium - 2 hard. We can categorized these 3 problems as the medium and hard, no easy one!

Sadly I can’t really join the competition, I just arrived from Purwakarta on Sunday evening and felt so tired (woke up at 1PM on the following day). Well, simply, I’ve tried the analysis mode.

Problem 1 seems to be the easiest one, at a glance we can directly see the O(N*T) solution, but it’s not sufficient, we have to dig more. Mathematically it’s not really hard to see that the sum of all numbers in t-time will equal to [(N-1)^T * init_sum]. So, mathematically the only problem is to count that value which we can solve within O(logT), but sadly if you use this approach, there will be a dividing-operation where the modulo arithmetic won’t be easy to code, I’ve tried this kind of solution and only got 6 testcases. Knowing that problem, we have to back to the pattern, considering the change of only one number, we can see that ith number in t-time will be [(N-1)^T-1 - (N-1)^T-2 + (N-1)^T-3 - (N-1)^T-4 + … ± (N-1)¹ ∓ (N-1)⁰]*init_sum∓init_1th_number. Now using this approach we can also do O(logT) code and there’s no more dividing-operation, yeah! Got fullscore with this approach. This approach is someway same as the 1st solution in USACO analysis. Surprisingly, this kind of problem can be solved using power of matrices like we do to count fibonnacci number. Kurniady and Suhendry tell me about it before the analysis came out, they were both successfully solved it (I think Kurniady just left one little thing so that his code didn’t got fullscore).

Problem 2 is suh a dynamic-programming problem. I stuck on the O(N^3) solution, don’t know what to do anymore. In fact the proper solution is working only in O(N^2).

Problem 3, umm, actually I don’t know what to say, the problem seems to be extremely hard, with those constraint we can directly know that only O(N) or (N log N) solution will sufficient. In facts it’s kind of hashing in graph. If I’m not mistaken, one of CEOI07’s problems was kind of this, but that was only hashing in tree, I think that was easier. As a matter of fact, I couldn’t solve that CEOI07’s problem, so I think it’s obvious that I’m still unable to do so.

Summarize, if these are real problems in a competition, optimally I may only got about 400 out of 1000. A little bit sad, realizing that among Chinese competitor I’m nothing, hehe… Applause for them!

Oh ya, several Indonesian competitors did the CHN07 in the contest time and here is their results:

Irvan Jahja 424
Timotius Sakti 370
Suhendry Effendy 280
Andrian Kurniady 224
Amal Syahreza, Timotius Chandra, Muhammad Irfan Alfarabbi, Risan, Reinardus Surya Pradhitya 112
Listiarso Wastuargo, Gerry Yulian 80
Izhari Ishak Aksa 56

Congratz to Irvan Jahja who got the highest score, did the contest very well (especially on the 1st problem). For the others, there’s still a lot of time to learn and practicing, hope everyone will be better. See u in USACO January Contest!

In last of 2007, 3 books are successfully shipped to me from paddyfield.com (first time I buy from that site), 2 of them are: “Number : Language of Science (Tobias Dantzig)” and “A Briefer History of Time (Stephen Hawking)”. I have known about those 2 books long before I bought the original ones. I think those two books are among the best scientific books in 21th century. I hope I can write some review about each soon after I finish read it.

Just for your information, if you want to buy something from paddyfield.com. I think their service is quite good, their customer services are very welcome to take care customers and the shipping takes only about 7 days to Indonesia, I think it’s fast enough.

Welcome 2008! Hopefully this will be another good year or even better than before…

I don’t say it’s resolution or plan or something like that, just things in my head now about this year:

1. Last year I still wore a white-gray uniform in my senior high school, but in 2008 no more senior high, just university. Yup, soon I’ll go to Singapore pursuit my undergraduate program, I hope it will be nice and useful for me.  New faces, new people, new culture, new system will face me. I have to adapt and be a better achiever there (moreover I have to keep my results so that I won’t lose my ASEAN Scholarship)
2. In financial perspective, I want to try not to use my parents money anymore, I’ll start to buy and pay everything by myself. Since I got ASEAN Scholarships, I think it’s possible (moreover I can try part-time work in my spare time).
3. I have to try to be a more punctual person since I realize that I didn’t do very well before, hehe…
4. I have been single for about 4 years, hehe… Until this post published still don’t know about “something”, but I think in 2008 everything will be clearer.
5. Hmm, computing achievements, my target in 2008 is to get the ticket for ICPC World Final and also I want to try to compete in TopCoder (for now, my target is yellow upper in algorithm), hehe…