Browsing category decision maths

Prim vs Kruskal

A student asks: How do you remember the difference between Prim’s algorithm and Kruskal’s algorithm? In honesty, I don’t. This is one of the things that REALLY FRUSTRATES me about D1: it puts so much emphasis on remembering whose algorithm was whose1 ahead of figuring out how to program computers

A student asks: I'm struggling with the simplex algorithm. How do I read the tableau at the end? And how do I pick the right pivot? The simplex algorithm - which is D2 for most students, but D1 if you're doing OCR - is frequently listed as one of the

Scheduling a Scrabble tournament

Once upon a time, there was a Scrabble tournament. Sixteen of the county's greatest Scrabbleologists descended on the venue... only to find the organiser had lost the fixture list. What the organise could remember was this: there were five rounds, and each player played each of the others exactly once.

Sorting a list on the fly

I was writing a sort of revision sheet the other day, and I'd written the questions in a sensible order, but wanted to shuffle them randomly so that students wouldn't know what's coming next. This is not the kind of thing Microsoft Word was built for. I decided to start

Those medalling kids: knockout tournaments and who wins what?

(This piece is based on a paper I read recently... but I can't find a reference for it. If you know which paper I mean, please let me know and I'll update.) There's a reason tennis knockout draws are seeded. I'll get to why in a moment. But first, let's

Why AV is bad (for the BNP)

I don't think that the benefit to one party or another is a valid reason to pick a voting system - but one of the features of AV is that it tends to select the least objectionable candidate. Here's a simplified example. Let's imagine we have four candidates contesting a