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Category Archives: algorithms
Counting coins
This afternoon, Matt Locke tweeted the following problem from his nineyearold daughter’s maths homework:
Posted in algorithms, Mathematics
14 Comments
Revisiting “On editing text”
This document is an incomplete draft. About two years ago I wrote about a categorytheoretic treatment of collaborative text editing. That post is unique in the history of Bosker Blog in having been cited – twice so far that I know … Continue reading
Posted in algorithms, category theory, Mathematics
3 Comments
The bicycle lock problem
Don’t lock your bicycle with a combination lock. Someone will steal it: I learnt this the hard way. It’s quite easy to open a combination lock by feel, without knowing the combination. Try it: with a bit of practice, you … Continue reading
Posted in algorithms, Mathematics
4 Comments
Beyond Bézier curves
There is a new feature of Pages and Keynote, not mentioned in any of Apple’s publicity nor in any press coverage I’ve seen, that is really very interesting. Perhaps it will even one day prove to have been revolutionary, in … Continue reading
“Venn diagram” partitioning
Paddy3118 wrote about partitioning elements in the same way a Venn diagram does. So, if we have sets A, B and C, the partitions are
Posted in algorithms, chatter
1 Comment
On editing text
Editing text is the opposite of handling exceptions; or, to put it another way, editing text is like exception handling but backwards in time. I realise this is an unexpected claim, so I hope you will permit me to explain. … Continue reading
Posted in algorithms, category theory
17 Comments
Something I don’t understand about homomorphic encryption
Added later: In retrospect, now I know a little more about cryptography, I can see that my confusion here is caused entirely by the fact that I didn’t know the meaning of the technical term “semantic security”. Ever since Craig … Continue reading
Posted in algorithms, chatter
6 Comments
Computing Fibonacci numbers using Binet’s formula
A few months ago I wrote something about algorithms for computing Fibonacci numbers, which was discussed in some of the nerdier corners of the internet (and even, curiously, made it into print). Several people suggested that Binet’s closedform formula for … Continue reading
What’s all this about mazes? A statement of intent.
I’m trying something that I think is going to be fun and interesting – and, who knows, maybe even useful. I want to write a program that allows “random access” to all possible mazes, and does it quickly enough to … Continue reading
Posted in algorithms, mazes
5 Comments
The worst algorithm in the world?
You know the Fibonacci numbers: 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, … Each number is the sum of the previous two. Let’s say the zeroth Fibonacci number is zero, so: And let’s say you … Continue reading