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Math & Algorithms

The most popular blog posts about math & algorithms on Hacker News. 2,391 posts.

Any year
32

Rolling Shutters

I remember seeing once the following photo from Flickr, and having my brain melt slightly from trying to figure out what went wrong: The issue was the propeller was rotating as the camera detector 'read out', i.e. there was some motion during the exposure of the camera. This is an interesting thing to think about…

37

Functorio

You might have heard people say that functional programming is more academic, and real engineering is done in imperative style. I’m going to show you that real engineering is functional, and …

39

The hunt for the missing data type

A (directed) graph is a set of nodes, connected by arrows (edges). The nodes and edges may contain data. Here are some graphs: All graphs made with graphviz (source) Graphs are ubiquitous in software engineering: Package dependencies form directed graphs, as do module imports. The internet is a graph of links between…

56

1/0 = 0

Disclaimer 2024-12-02 Since this rant is going viral again (again (again)), some disclaimers: I wrote this six years ago to “”“win”“” an ugly Twitter fight. I’m glad I anonymized the inciting tweet and hope I’m the only person still getting grief over this. The core interesting bit— why it’s mathematically valid to…

58

Suspicious Discontinuities

If you read any personal finance forums late last year, there's a decent chance you ran across a question from someone who was desperately trying to lose money before the end of the year. There are a number of ways someone could do this; one commonly suggested scheme was to buy put options that were expected to expire…