I was a problem setter and judge for the ACM ICPC Philippines 2014 National Programming Contest held last September 6, 2014 at the Ateneo de Naga University. (I was also a problem setter and judge in last year’s multi-provincial programming contest.)

There were 31 teams from 13 schools. The winning team was from Ateneo de Manila University. It solved all 10 problems in a little less than 2 hours. (The teams were given 5 hours.) The detailed results are here.

I provided two problems: “B” (Scrabble) and “H” (Boggle). My Scrabble problem was one of the easiest (26 teams answered it correctly) and my Boggle problem was one of the hardest (7 teams answered it correctly).

In an earlier blog post, I showed the solution to a first-order linear system of two (ordinary) differential equations with constant coefficients for the case where the characteristic equation of the (constant coefficient) square matrix has repeated roots. In particular, I considered the system $\begin{array}{rcl}\frac{\mathrm{d}x}{\mathrm{d}t}&=&ax+by\\ \frac{\mathrm{d}y}{\mathrm{d}t}&=&cx+dy\\\end{array}$, where $a,b,c,d$ are real constants and $x,y,t$ are real variables, for the case where $(a-d)^2+4bc=0$ and $a\ne d$. Now I look at the case where $a=d$. Read the rest of this entry »

I just learned through Fine Books & Collections that one of the Certified Guaranty Company‘s two highest graded copies of Action Comics #1 (the one with white pages) was sold on eBay last August 24, 2014 for US$3,207,852. (The other CGC 9.0 Action Comics #1 (with off-white pages) was sold in 2011 for US$ 2,161,000.)

I seriously doubt that there would be any other comic book more expensive than this one. (Click on the image to see where I got it from.)

I just bought two Maisto Volkswagen Beetles. These usually sell for around 80 pesos each, but there was a 10% discount on the day I bought them. Both are made in China and have metallic paint, black plastic windows, metal bodies, and plastic bases.

My wife and I like weird-looking vehicles so we seldom buy Tomica models because these are usually based on real-life vehicles. But now there is Dream Tomica, and we recently bought three of them (because these were the only Dream Tomicas for sale at the store).

I got a few more star notes. I’m selling these as well as the other two star notes I mentioned in an earlier blog post.

Yesterday, I did something I very rarely do: I opened a Hot Wheels package. I couldn’t control myself; Let’s Go is just begging to be ridden by a Lego minifigure. (Not to worry, I have two more unopened Let’s Go packages.) Unfortunately, the seat in my Let’s Go doesn’t fit Lego pieces tightly.

(While writing this blog post, I discovered that Let’s Go isn’t the first Hot Wheels car that can be ridden by Lego minifigures. It seems that this honor goes to Fig Rig.)
Read the rest of this entry »

I’m selling an autographed copy of The Sandman #50. This 52-page comic book was published in June 1993 by Vertigo, a DC Comics imprint. This autographed copy of the regular printing was organized by Limited Treasured Editions. Writer Neil Gaiman’s signature is in silver marker over the main logo on the front cover. Included is a print of a sketch of Gaiman by artist P. Craig Russell. The comic book and the print, together with a backing board, are inside a plastic bag sealed with a tamper-proof sticker. My copy is number 1900 of 5000. Although I’ve kept the package in a mylar sleeve, there is now some foxing on the print.

I’m selling a copy of Cerebus #0. This issue has two variants: the first printing has a gold logo and the second printing has a white logo. It contains reprints of Cerebus #51, #112/113, #137, and part of #138. The interior is black and white newsprint. You get 100 pages for the cover price of US\$2.25—a pretty good value when it was printed in 1993.

I’m selling a copy of Hepcats 1: The Special Edition, a 32-page comic book published by Double Diamond Press in 1991. It’s a reprint of Hepcats #1 (published in 1989) plus a 4-page Hepcats History 101 and a 4-page story What It’s Like to Be a World-Famous Comic Book Superstar. More information about the series can be found here.