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Ultimate Tic Tac Toe
Once at a picnic, I saw mathematicians crowding around the last game I would have expected: Tic-tac-toe.
Topics /
Math & Algorithms
The most popular blog posts about math & algorithms on Hacker News. 70 posts.
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42
In The Hitchhiker’s Guide to the Galaxy by Douglas Adams, the number 42 is the “Answer to the Ultimate Question of Life, the Universe, and Everything”. But he didn’t say wha…
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Statistical Formulas For Programmers
When someone says “7 is greater than 5”, you declare that they’re really the same.
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Deciphering the Business Card Raytracer
I recently came across Paul Heckbert's business card raytracer. For those that have never heard of it: It is a very famous challenge in the Computer Graphics field that started on May 4th, 1984 via a post on comp.graphics by Paul Heckbert ( More about this in his article " A Minimal Ray Tracer " from the book Graphics…
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Rotating Images
How to rotate an image, and a need trick to rotate a bitmap an arbitrary amount in a simple paint package.
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How to Fold a Julia Fractal
A tale of numbers that like to turn: a different look at complex numbers and the strange things they do.
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Two dozen mathematicians wrote a 600 page book in 6 months on GitHub
Since spring, and even before that, I have participated in a great collaborative effort on writing a book on Homotopy Type Theory. It is finally finished and ready for public consumption. You can get the book freely at http://homotopytypetheory.org/book/ . Mike Shulman has written about the contents of the book , so I…
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A non-mathematical explanation of one way functions
Alice and Bob are crossword enthusiasts. Every morning they rush to complete the Daily Telegraph cryptic crossword . One morning Alice fini...
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Creating Shazam in Java
This domain is available for sale. Check out price, information and more on Dovendi.com
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How far can you overhang blocks?
How hungover can you get? Kids blocks and Calculus!
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Reddit’s empire is founded on a flawed algorithm
Reddit has a bug in their code. This bug is currently present in their production platform, and has been for years. It affects one of the most important algorithms in the entire site, the “Hot” ranking algorithm for link popularity. It has real, demonstrable negative effects. It has been reported to Reddit’s technical…
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Visual Cryptography
How to create perfect secret messages that can be decoded using just your eyes.
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D-Wave: Truth finally starts to emerge
Wrap-Up (June 5): This will be my final update on this post (really!!), since the discussion seems to have reached a point where not much progress is being made, and since I’d like to oblige …
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How traffic actually works
Every so often this article makes the rounds and it annoys me. That isn’t how traffic works and the proposed solutions won’t fix anything. Maybe you can eliminate the annoying stop-and-go, but no one gets home any faster. In fact you can prove that you and everyone behind you get home strictly later than if you had…
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The StarCraft path-finding hack
StarCraft pathfinding looked impossible to fix until one ugly hack changed everything. Here's the trick that shipped.
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Why there is no Hitchhiker’s Guide to Mathematics for Programmers
For those who aren’t regular readers: as a followup to this post, there are four posts detailing the basic four methods of proof, with intentions to detail some more advanced proof techniques in the future. You can find them on this blog’s primers page. Do you really want to get better at mathematics? Remember when…
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How Advanced Is the NSA's Cryptanalysis, and Can We Resist It?
The latest Snowden document is the US intelligence ‘black budget.’ There’s a lot of information in the few pages the Washington Post decided to publish, including an introduction by Director of National Intelligence James Clapper. In it, he drops a tantalizing hint: ‘Also, we are investing in groundbreaking…
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How to implement an algorithm from a scientific paper
This article is a short guide to implementing an algorithm from a scientific paper. I have implemented many complex algorithms from books and scientific publications, and this article sums up what I have learned while searching, reading, coding and debugging. This is obviously limited to publications in domains…
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Bezier Curves and Picasso
Pablo Picasso Simplicity and the Artist Some of my favorite of Pablo Picasso’s works are his line drawings. He did a number of them about animals: an owl, a camel, a butterfly, etc. This piece called “Dog” is on my wall: Dachshund-Picasso-Sketch (Jump to interactive demo where we recreate “Dog” using the math in this…
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Wounded QR Codes
How do QR codes work? How much is it possible to distort one and still have it readable?
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English Letter Frequency Counts: Mayzner Revisited
Here's what we can do with today's computing power (using publicly available data and the processing power of my own personal computer; I'm not relying on access to corporate computing power):
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Bayes' rule in Haskell (2007)
Random code snippets, projects and musings about software from Eric Kidd, a developer and occasional entrepreneur.
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Ten Years of Purely Functional Data Structures (2008)
In 1998, I published a book called Purely Functional Data Structures . Ten years later, the book is still selling well. (Every time I get ...
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