## PCPlus 294: Learn to solve pentominoes

This article was just a great deal of fun to write. I wanted to talk about Knuth’s DLX algorithm (“Dancing Links”) as a solution to the exact cover problem. I’d already talked about Sudoku (a great demo of DLX) recently as an article in the mag, so there was nothing for it but to go for pentominoes, one of the other examples Knuth gave. And it gave me a great reason to bring out my old pentomino set that I was given as a teenager and futz around with it. Needless to say I’m still just as bad at solving it as I was then. […]

## PCPlus 293: Building an efficient dictionary

I think this is pretty much the last article I’ve written for PCPlus that discusses algorithms in a fairly formal sense. As I said last time, my editors and I have slowly been moving my articles towards more “how it works” topics than the traditional “layman’s guide to algorithms” subjects I’m perhaps better known for. […]

## PCPlus 292: The science of route planning

By March 2010, I was starting to move to a more “how it works” style of article to go along with changes in the magazine, rather than a “layman’s guide to algorithms” article which I’d traditionally done. This article on GPS systems (or sat-nav, if you’re in England) was my first real attempt at such an article: select some technology and explain its underpinnings for the lay audience. […]

## PCPlus 291: Behind the minimax theorem

For February 2010’s issue, it was time for a more heavy-duty algorithm together with what my editor called a fun element. So, enter minimax and two-player zero-sum games. […]

## PCPlus 290: Testing for randomness

A familiar topic for me for the January 2010 issue: testing a pseudo-random number generator’s (PRNG) output for randomness. I say familiar because I’ve talked about it before, most recently in my book. Well, OK that was 10 years ago, but still, the techniques don’t change. And it’s extremely fascinating, to boot. […]

## I have PCPlus Mail

I finally got round to reading the Christmas edition of PC Plus this evening and was pleasantly surprised to see that someone had written in about a recent article of mine: 10 mistakes every programmer makes. It’s going to be next year before I republish it here in this hallowed blog, but you can read it over at TechRadar.com right now. […]

## PCPlus 289: Solve Sudoku

So, a bit of fun for the Christmas 2009 issue: solving Sudoku puzzles efficiently. Not if you’re a human, you understand, unless you’re the type of human who likes programming, but from the viewpoint of discussing algorithms for solving via computer. Because, once you’ve programmed how to solve a Sudoku puzzle, it’s pretty easy to then generate puzzles to solve. […]

## PCPlus 288: The thinking behind neural networks

For the December 2009 issue I turned to the subject of perceptrons and neural networks. This one was very much written for the layman: I’ve never written a neural network in my life. […]

## PCPlus 287: Calculate degrees of separation

In a week when I completed writing my 50th article for PC Plus, it’s kind of fitting to also republish a hoot of an article that I really enjoyed researching. […]