The Geek Brewery

Ubuntu 9.10 alpha and beta release users may have noticed something very wrong with its NetworkManager. On those releases, NetworkManager won’t let the user edit default network settings through the NetworkManager applet even with sufficient privileges. Instead, NetworkManager will just revert the settings. Thus, deeming it impossible to set a static IP address using NetworkManager applet.

This bug has now been fixed on the version of NetworkManager preinstalled in Ubuntu 9.10 release candidate. This means users won’t have to worry about the upcoming Ubuntu 9.10 release.

NetworkManager is not maintained and developed by Ubuntu.

Get your potbellied pig to mate

Several hours ago was the 2009 ACM-ICPC Asia Regionals Manila Site hosted by the Ateneo de Manila University. ACM-ICPC is a programming contests in which college students are to solve a certain number of problems in a limited number of time, in yesterday’s contest ten problems in five hours.

UP Diliman had ten teams in total, seven SOGO teams from the University of the Philippines Programming Guild and three teams from the UPD Department of Computer Science. I was a member of one of the SOGO teams, the SOGO Virgins.

Results, results and results!!

Our team only ranked 26th out of the 55 teams, which was quite disappointing. Among the 10 problems given, we only had three accepted solutions out of the five problems we attempted.

The champion was from our guild (UPPG), the Mga SOGO ni E.T.. They solved all 10 problems in 1 hour and 59 minutes. They will be competing for the World Finals this February 1 to 6, 2009 at Harbin University in China. Other teams who solved all 10 problems sorted by time were teams from Ho Chi Minh City University of Science, National University of Singapore, Hong Kong University of Science and Technology and another team from UP Programming Guild, SOGOng Long Ong Moy Poso. The freshie team (2 Young 2 SOGO) from our guild beat us as they solved 5 problems in all. Woot! For more detailed results, you may check out the contest director’s blog.

Problems encountered!

Experience is the best teacher. We encountered problems on some problems.

Problem A. Given three points on a parabola, get the maximum height of the parabola. Since we don’t have a mathematician in the team, we had a hard time finding an equation with degree one for all variables. We had to force one of our teammate (out of 3) to squeeze all his knowledge on parabolas. When he found one, I immediately coded Gaussian Elimination Method for two variables and two equations. Gladly, our solution was correct thus accepted by the judges.

On the summation problem, we got correct answers for the sample inputs but it was too slow that testing it on borderline cases (worst case scenarios) won’t yield a result in a reasonable amount of time. Since no one in our team was a mathematician, we had trouble limiting our search space. Our program was so inefficient but right that we were not able to have our solution accepted.

The other problem we attempted was the A(H1N1) problem. Given a set of N people in a community with their locations and radius of contact and a person infected by A(H1N1), we had to compute the number of levels of transmission until the virus is contained. We recognized that it was a graph problem; people as nodes then connect an edge to nodes within the radius of contact of an infected person. We just have to perform a BFS (Breadth-First Search) on the graph and find the  level distance from the root to find the maximum level of transmission.

The algorithm above was correct but I made a mistake in coding BFS. I colored the node after dequeuing it from the queue instead of coloring it while putting it on the queue as seen in my code below.

Damn. I admit that it was my fault, not anyone else’s. Hmmmmf. Waaaaaa. What a shame. On the other side, it still yielded the correct answer for the sample input.

Lessons Learned

• Never spend too much time on a single problem. We spent too much time debugging the A(H1N1) problem.
• A team needs a mathematician. There were quite a number of Math problems. We were only able to solve one out of all the Math problems.

Random Stuff

Even though we did not rank well, I was still happy of the outcome. Because of this contest, I will never forget BFS anymore! Hahahaha.

I am looking forward to joining the same contest for the next years if fate will permit.

After Typhoon Ondoy hit the Philippines, this is only my second post across all my blogs. I’m now conflicted with final exams, requirements and other responsibilities.

The photo above is me, studying for my Math 54 final exams barely 3 hours from now. Good luck to me.

After all my final exams, we’ll be bracing ourselves for our last days of training for the ACM-ICPC Asia Regionals 2009 which is on the 22nd and 23rd of October. Woot!

After October 23, I’m more or less free-er than ever. I’ll be attending the Mindanao Bloggers Summit 3 (also my third MBS) on October 24, 2009 at Cagayan de Oro. I already booked a ticket to Cagayan de Oro. Sadly, I have to leave Cagayan de Oro for Davao the same day.

Wish me luck.

I did not have time to blog since Ondoy’s wrath as I kept myself busy with lots of stuff. And by the way, last Wednesday was my 18th birthday! Belated happy birthday to me. It’s been a long time since I had a personal post in this blog, waaaa!

I’m not good in putting things to order, seriously. That’s why I’d prefer making a roundup of my thoughts.

• This will be the shortest sem ever. Last June, the start of classes was moved by a week due to A(H1N1) craze. Last week, typhoon Ondoy also forced schools in areas under State of Calamity to suspend classes for a week. Add the numerous miscellaneous holidays such as the funerals of former President Cory Aquino and INC leader Manalo.
• It’s less than a month before 2009 ACM-ICPC Asia Regionals. It’s my first time to join the competition so I barely have an idea on how it will progress. I can only rely with my experience on our mock competitions.
• Long time no swimming. I missed our weekly Sunday swimming. It’s over a month since I last went to Amoranto Sports Center.
• Tried helping in relief operations. Last Sunday after mighty Ondoy poured a month-worth of rain in Metro Manila, I heard horrible news scoops in DZMM’s audio stream such as floods reaching the second floor, people stranded on their roof without food and water overnight, etc.I felt an unusual urge to help so I convinced my sister to go with me at Sagip Kapamilya. Throughout my four days there (mostly night to early morning), I’ve tried carrying sacks of rice and other relief goods. I’ve also experienced distributing relief goods to affected areas.
• We have plenty of generous people. I was overwhelmed by the volume of donations being dropped-off at drop-off stations. I never thought people actually donate in foundations. Some clothes they donated were even brand-new.I’ve also met this couple from King Air Trading who volunteered to deliver relief goods using their truck. Their truck, the one we’re riding was supposed to go to an evacuation center in Mandaluyong but people already left the center when we arrived. The couple took the initiative to go to NDCC in Camp Aguinaldo to ask for an alternative destination. It was almost 1am when we left NDCC for our trip to Marikina.
• The Internet played a crucial role in dealing with Ondoy’s aftermath. People used social networks to spread emergency numbers and other important information. Online spreadsheets were also used to compile a list of people that needs to be rescued. Digital maps were used to map drop off stations for relief goods, missing people and other relevant information.
• I’m addicted to weather satellite images. Yesterday, I started compiling satellite imagery from PAGASA.
• I have a new haircut. The other day, I was so bored that I stopped by to have a haircut. After getting a haircut, I was still bored that I decided to spend the rest of the night surfing the Internet in a coffee shop.

I admit that I’m not good in writing. I write in super simple English. Feel free to correct my grammar if you spot a grammatically wrong sentence.