There is a way to reduce this to a simple sub-problem. There are 2 parts to the explanation, the algorithm, and the reason the algorithm provides an optimal solution. The first won’t make sense without the second, so I’ll start with the why. If you think of bombing the rectangle (assume a big rectangle – … Read more
(Following up on the suggestion of @HelloWorld to look into sorting networks.) It seems that a 29-comparison/swap network is the fastest way to do a 10-input sort. I used the network discovered by Waksman in 1969 for this example in JavaScript, which should translate directly into C, as it’s just a list of if statements, … Read more
This problem calls for a z-score or standard score, which will take into account the historical average, as other people have mentioned, but also the standard deviation of this historical data, making it more robust than just using the average. In your case a z-score is calculated by the following formula, where the trend would … Read more
See Wikipedia’s article on Color Difference for the right leads. Basically, you want to compute a distance metric in some multidimensional colorspace. But RGB is not “perceptually uniform”, so your Euclidean RGB distance metric suggested by Vadim will not match the human-perceived distance between colors. For a start, L*a*b* is intended to be a perceptually … Read more
Taking E is the starting point of the ray, L is the end point of the ray, C is the center of sphere you’re testing against r is the radius of that sphere Compute: d = L – E ( Direction vector of ray, from start to end ) f = E – C ( … Read more
I found this page in my search and since cycles are not same as strongly connected components, I kept on searching and finally, I found an efficient algorithm which lists all (elementary) cycles of a directed graph. It is from Donald B. Johnson and the paper can be found in the following link: http://www.cs.tufts.edu/comp/150GA/homeworks/hw1/Johnson%2075.PDF A … Read more
I thought I might briefly mention my own polygon clipping and offsetting library – Clipper. While Clipper is primarily designed for polygon clipping operations, it does polygon offsetting too. The library is open source freeware written in Delphi, C++ and C#. It has a very unencumbered Boost license allowing it to be used in both … Read more
Not homework. My first job as a professional programmer (1995) was writing a genetic-algorithm based automated trading system for S&P500 futures. The application was written in Visual Basic 3 [!] and I have no idea how I did anything back then, since VB3 didn’t even have classes. The application started with a population of randomly-generated … Read more
Garry Tan posted a Javascript solution on his blog (which he attributes to a now defunct mjijackson.com, but is archived here and the original author has a gist – thanks to user2441511). The code is re-posted below: HSL to RGB: /** * Converts an HSL color value to RGB. Conversion formula * adapted from http://en.wikipedia.org/wiki/HSL_color_space. … Read more
How do you empty a vase containing five flowers? Answer: if the vase is not empty, you take out one flower and then you empty a vase containing four flowers. How do you empty a vase containing four flowers? Answer: if the vase is not empty, you take out one flower and then you empty … Read more