I was a problem setter and judge for the ACM ICPC Bicol held last August 10, 2013 at the Ateneo de Naga University. Programming was done using C, C++, or Java and judging was done using PC2. There were 32 teams from 15 schools (of these, 4 teams were from 2 schools outside the Bicol region). The winning team was from Ateneo de Manila University and solved all 10 problems in the given 5 hours. A team from Ateneo de Davao University finished in second place with 5 problems solved. (The detailed results are here.)

I provided two problems: “F” (Sharkovski’s Ordering) and “I” (Interior Lattice Points). The first was inspired by a 2008 paper by Ciesielski and Pogoda and the second by chapter 5 of Ian Stewart‘s *Another Fine Math You’ve Got Me Into…* (New York: W. H. Freeman and Company, 1992).

Problem “F” looks easy (16 teams tried to answer it) but implementing the solution could be a little tricky (only 5 got it correctly). Problem “I” looks difficult (2 teams tried to answer it) but implementing it is not so hard if you know Pick’s Theorem (both teams got it correctly the first time).